I've been using US post and Canada post with good results for the last 10 years or so. Couriers are way too expensive.
At this point I'm not ready to take on any more work.
I did look into it a few years ago but at that time there was very little interest. If I were going to put together the kind of head pkg that I do for the other stuff I work on, there would be a bunch of work involved like porting and flowing the heads, quality parts sourcing, and cam profile development. It's not fair to expect a few customers to pay for the development, and not feasible for me to do for small volumes, when I have other stuff waiting on the bench.
by the time you get all the port work done and a valve job (I have to farm that out) is takes a bite out of $1900 + I agree very few here will want to pay it.
On the other hand - its not that hard to do - takes time and if someone started to practice on a scrap head - then did their own - its maybe $300 in tools to do it + the valve job.
Try it - its only metal. The first port job I every did was way rough to what I can do know - but it still made a difference. Put this way, there is no way on this head to make the exhaust flow worse than it is.