I have the cat-back PV1 (purchased as part of the group by from Powervault/John Finnell) - it's a mandrel-bent SS tube extending from the back of the exhaust to pretty much the same shape as the existing VX exhaust - it even has the rear exhaust hanger so it's a direct bolt-up. The front flange is short but ends right where the crossmember and rear of the cat flange lie. It's not complicated and shouldn't be hard to mock-up. If you know someone who can bend tubing you can have the old removed and a new following the same pattern. Make sure you add a hanger to the front to support the weight as there were some instances of a broken exhaust manifold due to the stress (may have only been with the heavier PV1 though) - the original VX muffler bolts directly to the frame and you want to get that stress off - also if you don't have a hanger the front flange can clatter against the crossmember. I'll try to get you some pics this weekend if no one else has any.
FYI, the resonating tip actually hurts HP a little (supposedly) by constricting the exit tube - when Dave and I had our setups dynoed the sound was noticeably different - the guy doing to dyno asked about it. Now that I've got the SC on there I'm noticeing both a louder exhaust sound and also a "sucking" sound from the CAI (it vents to the fender hole so it's really loud with the window down).
-- John