Hmm, what I'd heard is that they'd thrown the PalmOS out of the window because it was a huge steaming POS and just grafted the Palm UI on top of EPOC32, which is a solid, extensible (etc etc) OS properly designed for portable devices.
There has been a lot of talk amongst Palm developers about how they're so amazed Palm's TCP stack actually manages to do *anything* as it's so full of holes & held together with bits of sticky tape ;)
Hugo
(who wrote the IMAP client in EPOC32 - ie, Series 5mx, Revo, Ericsson R380, etc. So I'm biased!)