Struggling Italian coachbuilder Bertone will have to scramble to come up with a new survival plan before investors meet this week after Fiat Group rejected earlier plans to help fund its rescue. Fiat’s CEO Sergio Marchionne said talks between the two over a possible joint-venture to build a new Lancia model fell through last week because the deal “was not a financially viable business case.”

Under the proposal, Bertone would build up to 15,000 Lancia coupe cabriolets per year from 2009, but now Automotive News reports that the cars will be built by Fiat at its plant in Turin alongside the Grande Punto on which it’s based.

Apparently, the two carmakers couldn’t agree on how much of Bertone’s original workforce would be retained, with Fiat demanding that half of the coachbuilder’s 1,500 staff be dropped. Bertone is not alone in its struggle. Its main rival Pininfarina was forced to trim its staff last year just to break even, as did the competition in Finland and Germany.

In the mean time, Bertone will start building campervans based on Fiat’s Iveco Daily commercial vehicle but will only need 200 staff to complete the job.