I have, on occasion, been party to doghouse recordings. The bleed has to become your friend so positioning is all important when micing only. That being said, the 'best' sound I was able to coax out of a 3/4 scale German box involved a Beyer M500 wrapped in foam and litterally stuck under the bridge. With this I had a 2' square piece of 1/2" plexiglass and a Crown PZM mounted to it on a mic stand out about 18" from the bridge. I gobo'd off the bass from the guitar amp and the drums and the piano was(thankfully) out in the piano room. While there was still some bleed, it wasnt obtrusive to that track and kinda fleshed things out at the mix. The bass was solid and had that 'woody' acoustic sound that we all love when we can hear it and distinguish it from the other instruments.
This was achieved after several HOURS of experimentation with mics and all things acoustic.