Sorry I am so late on a reply here to your question...but I am glad you are interested on trying some digital modes on VHF/UHF!!
I have not made any RTTY contacts on VHF/UHF but am sure willing to give it a try and see how it performs. There are a couple of spots on 6 mters where RTTY is listd...50.300 nd 50.700 so try those...go here:http://www.remote.arrl.org/FandES/field/regulations/bandplan.htmlhttp://k0swi.microlnk.com/LISTS/BAND%20PLAN%20VHF%20UHF.htmhttp://www.dxer.com/bandplan.html
50.300 or 50.700 rtty
If you are going to look for digital signals look around these areas.. 50.220 to 50.300 for 6 mtrs.... 144.110 to 144.160 for 2 meters....and 432.110 to432.200 for 70cm....don't limit yourself and try many modes like PSK, MFSK16, HELL, and the WSJT modes of FSK441 Meteor Scatter and JT44 weak signal modes. These frequencys listed are for SSB digtal and for sure try the set FM digital frequencys for those with FM radios only that want to try FM SSTV, FM HELL, or FM PSK modes.
Not sure that I gave you a good answer but email me anytime if you want more info than I can list or cover here firstname.lastname@example.org
....there is not much digital use or any "set" frequencys yet for many of the digital modes for VHF/UHF (unlike HF where is used by many and have a set list) but what better place to experiment with them all than on VHF/UHF....I would think in 5 or 10 years from now that some of this will advance more and more an be the norm for VHF/UHF.
GL and hope you try some contacts and enter you log for the first ALL Digital Mode VHF/UHF Contest.
de kb9umt Don EN50dp
(trying to promote more digital on VHF/UHF and experimenting)