I believe this UI improvement is trivial to make. Just add the following lines to the end of the "<ubcd>/pmagic/boot/syslinux/syslinux.cfg" file, and you can see the "Return to UBCD" entry in the PMagic boot menu.
Code:
MENU SEPARATOR
LABEL return_ubcd
MENU LABEL ^.. Return to Ultimate Boot CD Menu
CONFIG /ubcd/menus/syslinux/main.cfg
LABEL return_ubcd
MENU LABEL ^.. Return to Ultimate Boot CD Menu
CONFIG /ubcd/menus/syslinux/main.cfg