It's not really complicated to remove a tube from a TIG welded frame, just cut a chunk out of the dented tube, grind/sand off the old welds, miter a new tube and weld it up. If you are handy with a file and a measuring tape one could buy a new top tube from NOVA, do the coping yourself, cut out the damaged tube yourself and just take it to a regular welding shop, they charge less than framebuilders it seems to me.