At the rate this is going, I'll have to get myself a copy of that schematic. Seems that everybody and his brother has a 'Mini-A'...except that they all changed things around from what I did when I first posted the circuit. That's not necessarily bad, but it sure is confusing.
Just guessing...are R19, R20, R27, and R28 the resistors at the Sources of the MOSFETs and the output sense array?
If so, did you use 3W resistors?
Were you playing at full power? (Remember, 10W isn't 100W...full power comes earlier than you might expect. The Mini-A ain't a rock-n-roll amp.)
Were there any odd noises prior to failure?
Do you have an oscilloscope?