Well, tall is not going to be limited necessarily by the rim but as far as width, I've got 8.5" wide AG-type tires mounted to my stock wheels no problem.
I have 26 X 8 X 12 tires on my stock rims! But really go to at least 13" rims off of something from the junk yard! About everything Jap will be the 4 x 100 and then there is the 4 X 110 that will also be some Jap as well as German cars and others! Take your rim with you and try ? Remember you 12" rim wont fit on the cars with 13" rims because there brakes are bigger, but turn your rim backwards and it should go on?
