If there was ever a concept that seemed destined for production in the Audi factory, it would be the R8 TDI Le Mans concept. Based on the marque's tried-and-true diesel performance technology, the V12 diesel is a superb donk that might now go to waste, shelved in the wake of the financial crisis.

After teasing us all with reveals at Detroit and Geneva last year, and even allowing the media to drive the prototype with great written results, the R8 TDI program is reportedly on the rocks.

When it was first revealed last year, Audi said the R8 Le Mans was only a concept, yet the company's mission statement of being 'the first car manufacturer to offer a diesel engine alternative across its entire range', seemed to encompass a sparkless R8. Though R8 production remains small at about 25 cars a week, one Audi executive told Wheelsmag that the company "...does have the capacity to produce a limited run of a diesel R8."

The 6.0-litre TDI twin turbo V12 develops 373kW and 1000Nm, pushing to 0-100km sprint of 4.2 seconds and a 300km/h-plus top speed with a fuel consumption of just 10.1L/100km.

However, an unnamed source at Audi has today told Auto Express that the R&D required to re-engineering the R8 to house the huge twin-turbocharged V12 engine is not financially cost effective in the current market, and sales would never justify the investment.

Thankfully the 5.2-litre V10 is already in existence, and the Cabrio version remains a reality...