During the Petit broadcast S. Atherton said that beside Zytek there were 2 other mfgs working closely with ALMS/IMSA on the rules structure for hybrid equalization etc.. It seems that one of those 2 would be Peugeot as they have already run a hybrid-proto demo. Now it seems that the third one might be tied to the Dome S102. It is being reported that Toyota had talks with the ALMS at Detroit and the Dome S102 has been run with a Toyota hybrid system at Tokachi in July. In fact it seems to be the hybrid system that won the 07 24hr race at Tokachi in a Toyota Supra GT.
Story here, I could not get the article to translate in whole, so I did it a paragraph at a time.