I doubt it would take them much time to recompile their firmware with the new ADE. I think it would take more time for the quality assurance checks, but they could offset that by working with MobileRead members and releasing a beta firmware. I'm sure there are plenty of gullible people such as myself that are willing to be guinea pigs.
The ability to have both a PDF and epub library book checked out at the same time is a major flaw and should definitely be addressed. And in the process they might make a few other users, like myself, happy by using the newest ADE to resolve various formatting bugs and the ability to have fully justified text.
It's either that or wait for
ebookapplications.com to release their firmware for the PRS-600. They say they are working on one, but haven't release it yet. But they do have one already for the PRS-300 with fully justified text and many other features.
Etienne66