K180s on an XSR?
Hmmm....good luck with that one - sounds like a major, very expensive project! Even if you find wheels which will fit the tyres and the bike (this will be a challenge!), bear in mind that k180s have a pretty low speed rating.
Much easier to fit an off road style tyre to your existing 17" wheels...lots of suggestions in the tyres threads.
There are wheels available for around $2200 for the set from Motodemic - click here - you would need to specify the rim size desired. I'd recommend doing the 18 on the back for clearance purposes, It's a chunk of change to drop to have the K180 tread.
You might look at the Pirelli MT60 for a somewhat close tread style.