Oh pshaw. The SID will blow any generic-ass wavetable GM box completely out of the water for sheer sonic character. Hell, even Yamaha's old FM chips would outshine the generic XG crap they poop out now, if used well. And hey, Paula as well has its own particular character (thanks to the gritty early digital sound tamed by a bit of filtering,) even if it is just a sample-playback affair.
But it's silly to think that it'd be worth the trouble trying to create a dedicated module version; for one thing, as freqmax points out, Paula itself is only DACs and filters, and requires Agnus to actually get its data. For another, you need a system to load samples into memory, interpret incoming MIDI events, assign channels, and apply effects like volume envelopes anyway. At that point, you're already halfway to an Amiga.