The short answer is yes!. For example Leadtek has a card on it's website that is the "ultra" using 128 MB of memory. Some manufacturers gives me the impression of naming their 256 MB versions "ultra" and 128 MB version "non-ultra", even though they are both based on the NV35 "ultra" core.
Makes me wonder what they will call the NV35 Value that is rumoured.
Anyway, my suggestion is that you carefully check the specifications of the card(s) you are interested in to find out the operating frequencies and amount of memory. You would probably do this anyway, I'm just putting it in print