Yeah I dont see the problem either, if you dont mix companies models how are you ever going to support the small one man companies?
And besides the game was shelved before they got a chance to be released, so surely its alright in these instance?
First of I'd suggest the VSF range put out by Parroom Station, they have a very nice selection of martian savages, some incredible mounts, and if your really brave giant four armed Tharkians straight out of a John Carter book:
http://www.thelondonwarroom.com/Parroom%20Station%20Miniatures%20Index.htm#PARROOM%20STATION%20INDEX
Hmmm more Tawny thoughts coming through, thinderbolt mountain do a nice range of barbarian chicks riding terrorbird which might fit the part:
If thats not your cup of tea then theres the Vor range which had some skinny aliens with really nasty faces that have always put me off
somewhat, but they certainly are skinny, and brutish, and all of that
http://www.connectstores.com/ralpartha/sp_16726.html
Maidenhead miniatures make some very nice terrorbirds designed to be ridden by barbarian chicks wearing not very much but might fit quite well:
http://members.optushome.com.au/cynan/Miniatures.htm
If you dont mind supporting a company like Urban Mammoth then in the Void range you'll find some nice lizard mounts WITH gas masks!!!! (Just think no more stupid "So how does this methane breathing creature breathe away from its homeland comments)
The LKt beat to\ that one but these could be fun for scenarios too:
If I can think of more I'll post. I think Byrams a good poster on this forum to talk to he's pretty good at finding models apparantly