I feel that because there are so many changes being made to the style system that "style providers" are waiting for the ( I won't say stable) because xenforo is prity much stable but gold release. Personally I see the gold as a tag and doesn't deflect the quality of the product in it's early stages but other see a gold tag as a "ease of mind" a safety net so to speak.
Bare in mind, Stylers are in what I call the preparation stage. Getting fluent and familiarising themselves with the product ensuring that when they go live they are making use of the magnificent styling engine and thus passing that quality to customers.
Of course, this is mainly assumptions on my part and only the people who are providing can respond.
That is one of the reasons, why the sites you mentioned have halted skins for vB. Things are changing so much, that they are getting tired of having to do major fix ups. So they will wait it out a bit.
For now I say you should try to make your own and just wait it out.
I design themes and currently trying to get familiar with xF style system(creating themes that really are different from the default, layout-wise). So far, I quite got the hang of it. I am waiting for a stable release, just because it makes it easier for me and covenant for everyone else in the long run.
I designed a few themes for SMF(30+) when it went to RC1 out of beta. Then in RC2, they had a complete template rewrite, which totally screwed me. I would rather spend time writing new themes than constantly rewriting old ones. A person only has so much time to spend.
I plan to write a unique themes and sell them for about $10 each to anyone. I will not be doing any custom themes for individuals/sites. There will also be free ones based games, movies, etc. I plan to try and do 1 free and 1 unique them per month, or more. But again, we'll see based on my work schedule. I really wish I could do it full time to tell you the truth...