I am looking for a cordless phone (home phone) that has the following features: 
1) 5.8 Ghz   2) Multi-line (can handle two different phone numbers) 
3) Digital Answering machine for both lines   4) Can be expanded to
include additional cordless units.   The closest I have been able to
find is the Uniden TRU8866 (it has everything I am looking for EXCEPT
for the answering machine component). I am not really concerned with
the brand, Just want all these features on one unit.

I'm sure I'm running into the same brick walls you were.

I did a fair amount of searching but just couldn't find any 5.8GHz
phones that were both multi-line, multi-handset, and
answering-machine-inclusive.  I'm guessing it's b/c the 5.8GHz
spectrum is relatively recent for phones.  If you wait a few months, I
would expect Uniden to have a phone out that has all of the features.