Hi all,
i did not read this thread completely, but:
AFAIK it is no problem to use two major versions of a library simultaneous. So it should be possible, to install Qtopia 2.x libraries and applications onto a Sharp-ROM-driven device without braking the Sharp apps. I don't know, if the same applies to QT/E because of the access to the framebuffer device.
greets
Mag1c