Generally it is possible to install maemo apps onto easy debian, but depending on what rootfs you are using (Mer / Debian (Lenny) / Fedora, ...) there might be missing dependencies. Why do you want to do this?

It is also possible to use another /usr directory (on /dev/mmcblk0p4 for example) after the basic boot process or even to boot into Mer instead of Maemo. ext2 supports symlinks!