I have updated the dosbox link so contain a few versions based on the latest version in the repos. One has the same mouse patches disabled as my svn build, the other has a further patch related to vertical mouse scaling removed.

Additionally, I have found an old extras-devel version with all mouse patches but vertical_scaling enabled. Hopefully this lot will help track down the culprits.
http://maemo.org/packages/package_in.../0.74-0maemo5/