Richard Pollock’s Mule Motorcycles was covered here before but I stopped by his website and noticed he has a lot more photos up since the last time I looked. One project previously in progress has since been finished, the XR1660, and it is one of the best looking street tracker builds I’ve yet seen, though he has many others, many Sportster based, some XS650, some Triumph, but all very well done. A 1660? Oh, yeah!
If you like street trackers, you really need to check out his site.