At the size you're looking for, I really don't think you'll find much better than the CMC-8's. You could try using the AT853 caps with your CMC-8 bodies using the adapters. This will make the mics a tad bit larger on the front end, but the quality of the 853 caps is generally considered to be better than the 943's that the CMC-8 mics use.
Evan
QFT. The cardiods in particular have fuller bass response and overall sound. It depends what you like to hear, though. Some people seem to prefer recordings with no bass. I won't mention any particular makes/models of mics, but some of the more popular ones, to my ears, have no bass at all and folks love 'em. The 853s have a fuller sound.
At about that same size, you could look into Audix micro caps with Church active cables. Available in hyper, card and omni.
If you want to hear some examples with the 853s, try my Mogwai recording on 4/29/09 that is on archive.org. Not exactly "metal" but it's a very loud guitar-driven band. I actually used light bass rolloff for that one and it still has nice low-end response IMHO.