Hi Joseph,
A couple things. I was one of several folks who suggested to Mike L to use a HF trailer for his gasifer and it ended up being rather flexible for the task. I’d suggest to use a frame under the chunker and just have the trailer under it to make it mobile.
If you find proper sized pulley’s that need keyways broached in them I can help you out as I have dumont key broaching sets. You’ll probably be more successful finding taper bore pulley’s and just use the proper hub. I presume you already know they made a significant variety of designs. If needed - they can usually be re-keyed if needed. I’ve bored them out before too but feel it’s not worth the effort and time.
Best,
RonO