Frame Jig Suggestions?

[kend]

This Vega started out as a simple "get her running" project and now we're into replacing the entire cage as the tubing used for the cage that's in it now isn't thick enough. Before we start cutting the old cage out I'd like to get it set up on a fixture or jig of some sort to minimize distortion and I'm looking for info on home built equipment for that purpose.

Any suggestions or sites I can look at? Thanks