I didn't see another thread and since the search wasn't working I thought I'd start a thread.
Tennessee is still accepting applications and they still have some money left. They may get some more money next year too so it may be worth it to send in an application before the end of September. The program is first come first serve. They'll pay up to 50% or $4000 for a qaulifying APU.
Tennessee State Information
Application
Brochure
Press Release
type of APU
For People living in Arkansas, Louisiana, New Mexico, Oklahoma, Texas, Iowa, Kansas, Missouri, and Nebraska OOIDA is also administering a rebate program.
Link