Tnorris.. i think I know the answer to your question, but not so that they dont appear in one certain viewport. This will work most likely though. Take your refrence images and put them into a new layer (Channelbox/layer editor.. then go new layer, and then select the plains and right click the lair and assign to layer.) Now select the front refrence, and with the move tool.. drag it waaaaay back. Then with the side refrence, drag waaaay to one of the sides, then with the last top refrence, drag it waaay down. Now when you look at your image in perspective, those plains arent really in sight.. but when you go into the top, side, and front viewports.. the image will be dead on with your model. Side, front and top viewports act different in this way . Hope this helped. Oh, BTW... other than the ram.. do you prefer the tools in Maya more, and which do you think is more powerful? Cya.

Oh, btw.. then you can click the box beside the V in the channel editor/layer ediotor.. and you can put the images to R for refrence.. then you cant select them.