Originally Posted by cschreppel
The Earthworks PianoMic is excellent for live applications, especially if you can close the lid completely and have the FOH and/or Monitor engineer for the venue pump it through the PA.
If it's mainly an acoustic gig that you're capturing, I've been using my Sennheiser MKH8040s. I can get them in pretty tight and angle them for rejection from the bass and drums - the kit being the bigger culprit of low end bleed for me.
I've also had luck with SDCs that have a Fig. 8 pickup pattern where I'll angle the null toward the rest of the rhythm section.
What he said. Another solution is DPA 406x mics tight in (I mount them to the harp with small Alnico magnets and Velcro). They're omni, so LF boost from proximity isn't an issue, and they're about as close to the strings/soundboard as you can get, which attenuates the bleed about as much as can be had if the lid's up. Experiment with placement for the sound you want.
If the lid is to be down, closed or on short stick, a bit of gaff tape adheres them to the underside of the lid (they weigh less than an ounce) and the lid becomes a boundary. Again, experiment with placement. The EarthWorks placement is a good place to start.
And, not to steal EarthWorks' fire... a carbon fiber rod and gaff tape can, for $800 and change, pretty well duplicate the placement the EW rig allows.
Let us know where you end up. More information is always better than less!