I would have to say Audix mics are probably one of the best choices at mics that are affordable to most people and sound great in a variety of applications, stealth or not.
For stealthing, the Micros, which have been mentioned, are great. They are full body mics, but about the size of your pinky finger. You can get them in a variety of polar patterns as well. The low end frequency is not too bad either. The M1290s are more well rounded in that aspect than the M1245s.
The micros also work great for miking drums.
You can mount them onto custom shockmounts, or rig them with mic clips into a Schoeps A20 shockmount too. The M1245, the smaller of the 2 micros can definitly be mounted onto your glasses or in a cap with ease.
Any sample recordings of the M1290s I will be glad to provide.
Phil