I vote with Erik_S on doing some careful surgery....bypass the original dead amp, add a companion plate that could be housed separately....
That, of course, if you liked the Velo in the 1st place....?
Instead of boxing hassle + shipping costs + new plate + time involved, you could be good to go with a D mono sub amp......sooner...
Minimum moola, min mess, max magic mutant marvels....;)
Resale with no repair would be disappointing, esp. with that driver leaving your hands, and the replacement(s) an unknown ducats dent....
Your call, and good luck *S*