I grabbed the latest version from debian armel (sid) by downloading it from http://packages.debian.org/sid/armel/mtpaint/download.

After downloading the deb-package, I unpacked it and copied a single file (mtpaint) from the package's /usr/bin directory to /opt/mtpaint-debian/ (after creating this directory). I also created an alias in my /home/user/.profile so that I can start mtpaint by writing "mtp" in the terminal.

The program runs fine, it's fast, and even though it isn't hildonized, it's quite usable.