What are the differences between Longhorn frame and C20 frame?

[Onebean]

This is my first real post on the board. I just finished my introduction post.

Obviously the length is different, but is the Longhorn heavier duty or designed differently? I've been told the frames between C20 and C10 are the same, only the suspension changed between them. If I found a Longhorn frame, could it be shortened to a short box like the long box frame can? I seem to run into Longhorns quite often. I though they were a rare model, but they seem to be around in decent numbers. Thanks for your help.