Freedom Cycles might have something worth looking at, but they told me they only install them, themselves, that they don't sell them for you to install yourself. Not all of us live near them so that we can take our bikes there, or would prefer to do the work ourselves. So, IMO, that option is not viable for most people.
I too, am waiting to see what Zipper's comes up with but I also don't want to be doing this in Feb or March, so I may have to go with another cam just due to the timing of the release of the Zipper's package. I'm not trying to put anyone down here, just stating facts, as I see them.
What's a viable alternative for just a switch to gear drives and possibly no head work? I've found a few suggestions from cam manufacturers and builders, and right now I'm leaning toward an Andrews TW26G, but also looking at a Crane HTC-310-2 or possibly a Red Shift 557TC, but I think it might require head removal for spring work or clearancing the pistons.
Any suggestions for gear drive cams only? Preferably bolt-in's?
Hopefully, the Zipper's package will be available in time for installing yet this winter, but I also need to look into other possibilities, just in case.