I know the IMAI and Imex kits have shovels in them, I have quite a few. Most of them represent late 70's early 80's bikes which all had shovelheads. The only Knuckleheads are in the Revell chopper series which are getting stupid in terms of money on Fleabay. I keep an eye and they never go cheap. But perhaps a gluebomb would be a bit cheaper.
The Imai and Imex kits can be had cheap enough. I have 3 projects in various planning stages in the works and I'm basing them completely on those kits. Since I have a rigid Shovelhead I plan on constructing a replica of it as well as one of my Pops older bikes as well.
I think there are a couple in 1/12 that have Panheads in them as well. I think i need to look tonight and see.
They are great places to start.
thanx, now I gotta go lookin' for some knuckleheads and shovels