Hey Logan,
I so happen to know a trick for wheel conversion, not fork conversion.. You might like it. I had a XL500 1974 a couple years back wich i turned into a tracker. I wanted a smaller front wheel. In the first place because it's goes better in corners and ofcourse for looks. I bought an extra rear wheel and started taking the spokes apart as i wanted to use the rim only.
Now here's what i found out; The front hub has a large and a small flange. When you want to lace a rear-rim on a front hub, the spokes you allready have are a perfect fit! You can use the short set of spokes out of the front wheel for the large flange-side, and one set of rear-wheel spokes for the short flange side.
I even have some pics of it if you're really interested, but they're non digital so i'd have to scan them for you.
By the looks of it, this trick could work on a XL250 as well. After rim change there's no need to lower the forks. Lowering the forks on the massive front wheel (i did that in the first place) dramaticly changes riding capabilities for the worse. I strongly advice you not to lower your forks beyond the point of no return.
succes matey!