How well equipped is your shop or do you have access to equipment you will need? If you do you can modify units that are available. The trickiest part is to get the right geometry on the pedal shaft to where it works through the toeboard hole without binding. Making a frame mount bracket is no problem. On a 46 where the whole toeboard is removable you could disregard the existing hole, make a temperary cardboard one with a hole in the right place and then transfer that to the real one and just patch the old hole. On a 30 Plymouth where there was absolutely no room left over after an automatic trans was installed we ran a rod from the original clevis pin hole on the pedal shaft to a remote booster/MC mounted just in front of the left rear axle tube--a distance of about 4 ft. Works fine.

Evan