Real World Ideas

Pairing a decent shotgun microphone with some equivalent quality
figure-eight microphone (something like a Rode NTG-3 and NT2000) looked
like an interesting idea, although something like this clearly does not
meet my "fits in my day-sac" requirement.

Today I finally discovered the Audio-Technica BP 4029:

<http://www.audio-technica.com/cms/wired_mics/9087c643d6d7530f/index.html/>

which seems to do what I am looking for, and will fit into a standard
Rycote blimp like the one I am already using.  Still not a day-sac fit,
but I was carrying one of these things around already.