Here is someone that has done tri-color, the site is in French but a Google translation is here:
Original French Page:
Instructions on how to make Autotype Trichrome Carbro prints (including recipes) + other methods to reproduce colour:
or you can try 3 layer Gum Bichromate prints as here:
I think that all the processes are somewhat difficult to do in a home darkroom except the gum bichromate the problem is achieving an acceptable color balance.
you could shoot the film with the cmy filters
and send the film off to dr5 and have chromes made from your film
and then dye them, and stack them if it would save you the half tone step.
That's cool John. Have you tried this? Sounds neat.
nope, haven't tried it, but i would like to