I made a custom header and exhaust pipe for my AW Edge, because no standard header would fit. I bought some peices from Aircraft International and built a jig fixture to hold the parts in place. I took it to my local welding shop and about $50 later I have a great looking header. Sure I could probably have learned how to TIG weld, spent hundreds of dollars on weird fluxes, torches, and rods, but I'm getting lazy!
This is not a specialty shop, just our local welding shop, so I would think you could find one that could do the work. As for Keleo Creations, Kelvin is great and I'm sure could make you anything you'd like. He's currently working on two (soon to be three) scale exhausts for my warbirds.
Sam