You've got an AF and I've got 17" SuperMoto wheels that will fit it HEHEHEHE
On my XR650 SuperMotard I had Jeremy Wilkey (MX Tech) lower the suspension 4" (both ends) and revalve it for pavement/ hardpack use. I've ridden a few that were just lowered without the revalve and they didn't work very well on asphalt. My XR was an incredible slider on dirt or pavement. Backing it into the McDonalds parking lot was easy even for me :)
Standard Motard setup is 17"x3.50" wheel with a 120/70 tire on the front, 320mm floating disk (I used a Braking floater), stainless line and stock Honda caliper (you have to mill the backside of the caliper to make it fit). Performance Machine makes a super light 6 pot race caliper but you are looking at about $450, and flipover stoppies if you get to aggressive. Rear is 17"x4.25" wheel with a 150x60 or 160x60 rear tire. I ran the 150 so I didn't have to trim the edge of the tire. I hated the way the 160 felt, but FAST guys tell me that once you get over the quirks of the 160, it's the better setup. Most guys seem to run Talon hubs with Akront rims. White Bros sells the complete setup, and I was told Kosman does as well but I've never verified Kosman.
I'm setting up my YZ444F for SuperMotard/DTX work with 19" wheels at both ends and Maxxis CD3 & CD5 dirttrack tires. I'l be riding soon and will pass along how it works. I also have a 17" wheel setup for it like I described above. It should be interesting to see which is the better all around setup.
You'll have a great time Motarding you XR. It's the most enjoyable biking experience I've ever had.
http://www.ericgorr.com/images/future_thump.jpg