I am in the process of motarding my 89' XR600R. I plan to swap out the entire front end (forks, brakes, wheel, triples, calipers, etc.) with that from an early 90's VFR. The VFR triple clamp requires the use of a modified XR centershaft to accept available tapered roller bearings. If you are interested in this, check out the second link. Even though it is for an Xr650R, you will get an idea for what is necessary. VERY INFORMATIVE!! He adapted an entire F3 front end. If you only choose to swap out the front wheel, you will most likely have to spec wheel bearings, make wheel spacers, as well as fabricate a bracket to relocate your brake caliper due to the larger brake rotor of your "street" wheel. A stock Honda Hawk (NT650) rotor is (I believe) 320mm. SuperMotoJunkie.com has LOTS of great info for street conversions! I'll post up picks as I make more progress. For the rear I plan on using an F2/F3. I haven't decided... The F2 is a 4.5" while the F3 is a 5" rear. I also plan on setting up my front end so I swap out only the front wheel if I find myself doing a lot of offroad this summer.
Anyway, If you are interested I'll post pictures when I make more progress.