Low profile basement toilet drain fittings...??

Hey, first time posting, but I refrence this site all the time... so...

Heres the deal. I want to put a toilet in the basement where the flange is going to be 3' from the main stack in the basement. I don't want to take up the floor to run it because the main goes directly through the B-dry system and I'd rather not mess with that. Getting an upflush/ macerating/ specality kind of toilet is out of my price range so I decided, obviously, that I'd raise the floor. I'd really prefer not to go over 7 in high, and with the pitch and width of the pipe that seems totally feasable... My question is what kind of couplings/ fittings can I use to minimize the height that I have to raise it? I'll be going from cast Iron to pvc. I've looked at a couple of no hub couplings but between them and the wye I'm going to be looking at almost twice the height. I know this has been done before, what do you suggest??

Thanks in advance!