Looking on Mulsannes's Corner there's a link to a new championship in the USA based on FIA Group CN/C3 regulations, effectively replicating the European VdeV series:
http://www.modernendurance.com
Seeing as IMSA Lites is currently limited to 2 different chassis manufacturers, this series possibly opens up the sportscar scene in the US to more of the established manufacturers previously mentioned in this thread.
Additionally, the support of the ISCMA for the championship makes me wonder if this could be a step towards some overall LMP3 chassis regulations...?