Ya, that's a tricky situation.
Kooks has sent me their mid-length headers for the S197 but I cannot see them clearing the firewall but they want me to test.
The heads on this new 5.0 are different, bolt pattern, etc.
What I think is ideal is to have someone that has a jig for 4.6L headers, to fix it so they could weld on a 5.0 flange and make the necessary adjustments to make it work.
That would allow us to use any X-pipe or H-pipe from any company and any aftermarket type exhaust.
I'm trying hard, I have talked to several companies, nobody has budged yet and I think it's a market that they should be in.
Ford Racing is getting tons of orders on the new engine and swap parts, so having a set of headers in stock and ready to ship is a winner for whomever will pull it off!
Mike