I am thinking about going the same route as you skizzer,
the FR of the Crown amps I have looked at are almost ruler flat (+ 0dB, - 1dB)
, but as Nav pointed out, the balanced to unbalanced connection, of a pro to consumer product may need some attention; I think any new Crown amp would only have balanced XLR and 1/4 inputs, you would need some adapters, or a bal/unbal converter, Parts Express has at least one: Part Number 245-868.