Bump.
I saw in the virtualbox manual that you have to add an entry to the xorg.conf to get the mouse working properly, but it gives no example, only a example for the monitor settings. Tiny Core uses some sort of "conf-less" mode where xorg figures out stuff automatically. However, I noticed you can override this with a custom xorg.conf that contains just the entries you want to change. So that leaves me with two questions. What do I need to add in the xorg.conf? And how do I get virtualbox and /dev/psaux to talk to each other? This shouldn't be hard to figure out, mouse integration works great on every other major Linux distro in existence.