Thanks all and thanks for the offer Larry, not quite sure what I need just yet.
I've got the 2hp HF, so I can either pull the splitter off and go from the 5" inlet to some 6" pipe (what is available at the borg) , check with a local plumbing supply to see if 5" pvc is available, or just run two 4" runs, which may work fine for my layout. I've also seen where folks have removed the front plate with the 5" inlet on the DC and replace it with 1/2" mdf with a 6" connector added.
So is dust collection anything like trying to pump water up a wall (think sump pump)? Is there any noticeable suction loss if the lift was to be 10' - 12' high and 30' - 50' in length?