A thought (and maybe someone else already had it....if so my apologies)...
Is is likely that the mower for the electric ox (http://www.electrictractor.com/html/multi_prod.shtml) can be used a replacement for the ET's? Futhermore...what about the motors? They make a 36v system and the mower looks a great deal like our own. This (if it worked) coupled with the All Trak controller might solve the bulk of our supply problems?
Steve