IIRC, X-Force has some models, MagnaForce has some, Texas Star has some HD models. X-Force/MagnaForce used to make decent quality boxes, with HD models in their lineup. I used to run an X-Force 200HD box. Not sure about quality now, though.
TS used to make several HD models as well, decent quality (at least better than the rebadged generic amps - there were several different brands of amps that were all pretty much the same thing, right down to the faceplate - only the name of the company screened on the faceplate was different).
If you want to really get serious, you could look at comp boxes like davemade or fatboy.
as long as you get a reasonable wattage, you can get by with a stock alternator, but you may want to upgrade your battery.