This should be an easy afternoon project, after a visit to a hardware store, a thrift shop, arrival of a little plastic shoe-block-off doodad from the online retailer of your choice, and an hour or so on a workbench or the dining room table.
I'd find a busted camera that the shoe can be yanked from then, get the 90 degree small L bracket you bought at the hardware store along with either epoxy, liquid nails, or JB Weld, then fasten the two, so you can mount the finder. Then get the plastic shoe-block-off doodad you ordered from the online retailer of your choice and fasten it to the other side, so the bottom of the L sits in your camera's shoe.
Surely, someone out there has either 3D printed just such an accessory or had it CNC milled, either way, those sound expensive compared to the $3 I spent in my mind working up this solution. I don't think adhesives count as part of overall expense since they will be used for other crazy projects in the future.
The most elegant solution would be a finder which has had the foot re-mounted 90 degrees off, but I would only do this with one of the old square Leica junk plastic finders or something like an accessory finder from an FSU camera but those can still run up in the cost. Good luck!
Phil Forrest
