I've mentioned my Shure SM57 with the TAB Funkenwerk transformer upgrade, as being smoother and more open than a stock '57 These upgraded Shure's are available through Zen Pro Audio. Over at Gearsluz, an engineer just A/B'd a modded SM7b against stock. sm7b-t58.mp3 sm7b.mp3 I haven't priced Zen's upgraded SM7, but the TAB 57 runs $200.00 They sell them pre-modded, but will also retrofit stock mics for a reasonable fee. I'm a spazz with a soldering gun, so I don't feel comfortable doing a mod like this myself, but if you're handy, the mod should be pretty straight forward if you want to do it yourself.