Yes, the mouse does work ok (plug-n-play) in Qtopia if I install inputhelper_1.0.1-1_arm.ipk.
It has a cross-hair type of cursor.
The cursor also displays and moves around the screen in Dosbox, but pressing the buttons has no effect.
It also causes Dosbox to terminate unexpectedly.
I'll check out input-modules-2.4.20_1.23-lite-1_arm.ipk.
Thanks.
Side note...
I also have Dosbox installed on my windoze laptop, and it recognizes the touchpad, which is a PS/2 device.
If I plug in the same USB mouse, it also works fine.