Man I hope you're wrong about the longevity of rebuilt BMW transmissions. The estimate from the dealership had the parts price around $3400.00 for a REBUILT transmission. There is an outfit in Phoenix that has the transmission for $1950.00 and they'll include a four year warranty for like $450.00. It sounds like that would be 450 well spent if you're right.
Transmissions are easy (once they're out). I know the electrohydrolic BMW transmission are a lot more complex, but it's basically the same beast. I would just like to see some schematics before I open the case. I'll let you know what I find out.