http://www.tmuscle.com/free_online_a...r_bodybuilders
I've never tried the DB exercises that simulate cross, planche, or maltese; but I did use a cable pulley machine to work MU and crosses.
Unfortunately, none of these simulate the instability of the rings which is why spotting or assisted spotting (harness and pulleys/dream machine, trainers, block/bands) are probably superior to the DB exercises alone.