No dice.
I feel your pain.
No there isn't any aftermarket Subframes for this car. That's too bad since they wiegh something like 100lbs each. I'm sure a quality tubular frame made from fully welded chrome moly steel would pare about 75lbs of weight from that.
Anway, other than getting something custom made there is nothing.
One guy here who rebuilt his rear subframe did weld it up better and added some additional bracing for the heavy loads of drag racing. I'm sure something could be done to the front subframe too.