The AVID machines are quite capable. I helped my buddy order a few parts from 8020.net to reinforce the exiting structure (extra extrusions, cross-members, gussets, etc.). I think he spent about 300-400 on parts/shipping and it made quite a bit of difference after we stiffened up the base.
I think that's where the steel welded machines have a huge advantage, but it comes at a real cost in $$$ and weight!