FBReader now supports ePub, so that would be a great option. Since it doesn't deal with DRM'd books, it shouldn't conflict with any other business commitments.
If you offer a version in Linux, I'd be
very interested. I probably wouldn't buy a WinCE unit. If you provide and support an SDK for a Linux model, I think you'd have a horde of community developers willing and able to provide extensions, based on what's been happening with other vendors. Take a look in the iRex iLiad forum here, if you haven't yet.
