I have to agree with Filark
on this. I see no reason to upgrade just to get the market or whatever they call it now because it can cause more problems that it, maybe, solves. Problems with library, apps being updated and then not working and so on. Most apps can be found on sites other than the market - I always look on http://www.freewarelovers.com/android
for a start, then there is http://www.slideme.org/
and a few others.
Most people forget the EE and PE are running a very modified version of Android v2.2 and most new apps will no longer run on what we have. What we need is someone with the expertise and time to reverse engineer Ermine and find out what the specific parts that run the e-ink are and then see if they can be added to Android v2.3, or the tablet version, and give us a working unit, remembering the EE and PE aren't a phone and have very specific electronics as well as an old, now, processor.