In the year 2000, the Deep Emerald Green paint on Conan O'Brien's 1992 Ford Taurus SHO was perhaps a bit shinier. Oh, and Fiat Group CEO Paolo Cantarella declared Alfa Romeo would make its most triumphant arrival to the U.S. by 2003 with the latest Spider. We Yanks have tasted the 8C Competizione, 8C Spider, 4C, and 4C Spider between the millennium's start and now. Still waiting on the Spider, though, plus the discontinued 159 and Brera backordered from 2008.

Mahindra TR

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As listless Alfa dawdled over its U.S. return, Indian conglomerate Mahindra pitched the prospect of turbodiesel compact pickup trucks with 30 mpg highway in 2006. Initial interest soared. It was a downward spiral from there, culminating in lawsuits (of course) and an everlasting reminder of the hardships faced when breaking into the U.S. auto market. Early EPA numbers for the four-wheel-drive TR40 were an underwhelming 19/21/20 mpg city/highway/combined.

Pontiac G8 ST

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True story: Pontiac let the public suggest model names for the G8 ST through online submissions, and the winner was "G8 ST" (as it had started with). Pontiac's flared nostrils looked fantastic on the Oz-sourced Sport Truck, and a 361-hp, 6.0-liter V-8 resided under the hood of what was pegged for a 2010 model. Too good to be true? Well, we all know the ultimate fate of the Arrowhead's brand and this lifestyle pickup.

Infiniti Q50 Eau Rouge

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Like the G8 ST, the Q50 Eau Rouge is the sexed-up version of an established model. The Eau Rouge was to serve as Infiniti's halo/image vehicle, cramming a 560-hp, 3.8-liter, twin-turbo V-6 ( la the Nissan GT-R) into the brand's smallest car (until the Q30 arrives). It's dropped off the radar ever since former CEO Johan de Nysschen decamped for Cadillac in July 2014. The outspoken de Nysschen claimed to be the Eau Rouge's motivating force, unsurprisingly, via social media.

Ford Fusion GT

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In early 2008, we acquired intel on the Fusion GT, christening it "a kind of poor man's Audi S4." Tabled the same year because Ford aimed to conserve the GT's EcoBoost 3.5-liter, twin-turbo V-6 for other vehicles, the high-performance Fusion was supposed to finally emerge for the current generation. Now three years into the lifecycle, a 300-plus-horsepower, all-wheel-drive Fusion seems unlikely in the near term.

Mazda6 (diesel)

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Like the Fusion GT, the fantastic Mazda6 is waiting on an engine. Originally confirmed for a 2013 introduction, the 2.2-liter Skyactiv diesel four-cylinder remains persona non grata in the U.S. because of rigorous internal emissions and performance targets. Mazda overtly affirms its commitment, though our backchannel contacts tell us the engineering manpower supporting the U.S. Skyactiv-D program has been ominously reduced.

Fisker Atlantic

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A fair number of Fisker Karmas roam near MT's California headquarters, but we may never see an Atlantic. The plug-in hybrid equivalent of the everyman's Tesla Model 3 (an EV we're semi-patiently waiting for) was projected to enter production by the end of 2012. Then 2013. Then 2014 or 2015. In 2014 the company's bankrupt remains were scooped up by Chinese manufacturing powerhouse Wanxiang Group, which is trying to rebrand and relaunch the Karma.

Audi Quattro

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Two Quattro concept cars bowed over the past five years, one at the 2010 Paris auto show and one for the 2013 gala in Frankfurt, each enjoying the on again/off again cycle of predicting production timelines. A heritage-honoring opportunity that is still a great brand polisher, the earliest we could have witnessed the real life, 21st-century Quattro was 2013. The most recent reports say the lightweight, tech-heavy Quattro is on; we'll believe it when we see it.

Smart Formore

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DaimlerChrysler's baby brand announced, "This vehicle will also mark the company's entrance into the U.S. market [in 2006]." The Formore crossover would have been a natural fit nowadays, but it never even made it to its scheduled 2005 Frankfurt auto show unveiling. Smart's playful-looking, gas-electric hybrid Crosstown (with a Wrangler-esque collapsible windshield!) grabbed the attention in the Formore's stead, which was most assuredly not moving beyond the concept phase.

GMC Granite

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Will a bona fide standalone GMC vehicle ever be a thing? The compact Granite looked like it was on the right track from the moment it rolled on stage at the 2010 Detroit auto show, what with its rear-hinged passenger doors, fashionable interior, and stubby looks. Mass production was all but a given, except the planned 2013 model never materialized. Just to tease us more, company designers concocted a handy pickup truck version of the Granite, too.

Jaguar C-X75

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2010 proved to be the year of shaky promises, including the C-X75. Jaguar's plug-in hybrid hypercar would have been mentioned in the same breath as the Porsche 918 Spyder, Ferrari LaFerrari, and McLaren P1 had it hit the road as intended. After a total of five validation prototypes, the endeavor was toast by 2012's end, with an inadequate business case acting as the guillotine. All we can do now is continue waiting for a new-age XJ220.

Volkswagen Microbus

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One time-honored motoring trend is to speculate how and when Volkswagen will raise the Type 2 from the grave. But in June 2002, it appeared deducing would be a thing of the past when VW settled on putting the Microbus concept from the 2001 North American International Auto Show into the pipeline. Targeting the U.S. and especially surfer-happy California by 2005, the plans almost immediately hit the skids. And then we got the Chrysler Town & Country, err, Routan minivan.