ok I need ideas on how to do this

[rossb]

Steve I have been thinking about this and I like the idea. Naturally the center brace prevents the tank from bowing out. An external brace would also work but why not a glass internal brace? You could drain the tank down about a foot or so, use some wood clamps to temporarily replace the internal brace, cut out the center brace and then add a 1/2" X 2" X 6' (or so) glass brace inside on each of the two long sides. If they were siliconed in properly it would work quite well...
and then no rusting ... or wet wood ...
IMO