I think a 360 slim would be cool, but I would question whether it is actually worth doing, and as many of the comments above have said, I would rather they sort out the heat issues etc... coz 54% failure rate is just crazy.
Personally, I have been pretty fortunate in this regard; I bought my 360 way back in 2005 when it was released, and its still running just fine, it did go through a brief period of overheating, but since the warrenty had already expired, I opened it up and cleaned 3 years of dirt (scrummy) out of it, and has worked like a charm since then. One of my friends however was less fortunate; he's on his third.... lol