I did find a set. Sorry, not for sale - I'm going to use them on my Fire Am build. However, recently I looked into the cost of getting them replicated in stainless steel., since these are used and I'm not sure how long they will last being run on a car. There is a shop in my area that specializes in making custom headers and has done some impressive work fabricating headers for exotic cars. Anyway, they said that it would "require a healthy budget" in view of the complexity and tight fit, and that they would be trying to eliminate the "aggressive clearancing" on the front passenger side tube. They estimated $5500 - $6000 (CDN) ( $4300 - $4700 US) to build a replica in 304 stainless. If they made more sets after that, the cost would be about 10 - 15% less for subsequent sets, so $4675 - $5400 CDN ($3668 - $4237 US). That's still a lot for a set of headers.
I had heard that NPD was going to be producing them along with their other VSE parts, but nothing seems to have come of that. I would imagine that their costs would be somewhat less than a one-off by a specialty shop, but even if they got them to $3000 or so, you still need the fancy VSE aluminum oil pan and pick-up for them to fit, and I would imagine that would be at least $1000 US; NPD isn't producing that either. I don't know why they haven't moved forward on the 180 degree headers, but it seems possible that they just didn't think that they could sell very many if it was going to cost $4000 to run them.
I also remember that VSE did list the 180-degree headers in their first catalog, and they were $260 at that time; the aluminum pan was $215. For comparison, the Holley 850 Double Pumper was $172.20. By 1981, they had replaced the 180-degree headers with Hooker Super Comps at $236 (or $159 "Racer Net"). So VSE discontinued the 180-degree headers "back in the day" for some reason, and the reason doesn't appear to have been cost, exactly, since the 180s weren't that much more than the Super Comps. But who knows - it could be that they lost their fabricator, or they found that people weren't buying the 180s because they looked like a PITA to install.
Edit: I see that Doug's Headers makes 180-degree headers for Ford 390/427 for about $1200, so I would have thought that NPD could have them made at a similar price point, but I don't really know that.
Anyway, here are some photos, if you've never seen a set.
