I use AT853s as well. I wouldn't say the hypers are terribly lacking in bass, but certainly they pick up less bass than the same mics with omni or even card capsules (I've used them all). The uniguard capsules from the new U853 line do pick up a bit more bass than the old style, at least for the hypers, the only capsule where I've tried both generations.
The AT853 is probably the cheapest stealthable hyper option worth considering. A step up in price and size would be the Audix Micro 1290hcs, they border on being too big to stealth with but it can be done. Then another big jump in price (but down in size, though still bigger than the AT853s) and you can think about the active versions from MBHO, Neumann, and Schoeps.