HI Matt,
Good to see you again!
I'd second Chess' recommendation of
the Studio Projects C-3, which by being multi-pattern opens up the sound quite a lot and is a stone bargain at $349.
I suspect the main problem for you will be finding the right working distance, which may also explain why someone has told you that small condensers (from a considerable distance, I assume) might be better.
A super-cheap alternative to small condensers are
the Behringer ECM8000 omnis that are available from 8th Street Music (and other vendors) for about $76 delivered (per pair!). You'd have a friend find the two places in your music room where your voice and piano sounded best, and place the omnis there. They will record, then, the piano, your voice, and their interaction with your room in a way that close-micing will not. It takes some experimenting to get it right, I'm told.
I'd love to know what the decibel output of your voice is at 12 inches, 20 inches, and about three feet. The chances are your dynamic *range* is just incredible, and capturing that is going to require not only a great mic but also very careful placement.
I'm excited for you and look forward to hearing more about your successes.
Best wishes,
Mark H.