After some experimentation, I've discovered a rather hacky way of removing the android mouse pointer. As anyone else who has tried can attest, it's rather annoying having it as it moves out of sync with the pointers displayed in emulators like UAE4all2 and ScummVM. Be warned, this does involve altering a core system APK file, so make sure you backup the file before you proceed. You will need something like Root Browser (available here:
https://play.google.com/store/apps/details?id=com.jrummy.root.browserfree&hl=en) to alter this system file.
1. Take a backup of the /system/framework/framework-res.apk file onto your SD card
2. Take another backup of this file on your PC (just in case you need to restore later)
3. On your PC, open the APK as an archive with something like 7-Zip
4. Delete the /res/drawable-hdpi/pointer_arrow.png file
5. Copy the new APK back in to the /system/framework folder (without the mouse being connected)
6. Reboot system and you should no longer see the pointer when you connect the mouse
I have tested this method successfully with both stock ROM and Skelton's excellent new Legacy ROM. Both work fine for me. I wonder if Skelton might consider doing a pointer-free release at some point.