All the popular radio TTL flash triggers, like PocketWizard or RadioPopper, seem to be only available in Nikon and Canon flavors. Are there any models capable of transmitting Pentax P-TTL data?
This radio trigger appears to support P-TTL and high-speed sync.
I found this in this dpreview forum thread: http://forums.dpreview.com/forums/readflat.asp?forum=1036&message=40799541&changemode=1
So, having looked for some for a while, I'm going to have to sadly put forth "No" as the answer here. The TTL features of the radio triggers are relatively new, and their makers have (reasonably enough from a business point of view) gone with the market dominators first.
Hopefully, they keep hearing enough from Pentax users that they'll consider the smaller niche worth investing in eventually.
Personally, I keep holding out hope that Pentax (and now Ricoh) will simply include radio triggering as a basic feature built into an update of their flash system — but that's pretty much just a fantasy at this point.