I'm using one of these octopus hubs like Atarii has (or something close, but involving more soldering...) Main difference is I'm using it with no adapter; the mini-B is soldered for OTG, and rewired for the host side of the hub. (Since mine had only one host connector, that's become the power connector.)
This should be equivalent to Atarii's setup, but with an OTG-wired adapter (e.g. from jolouis) instead of the female-female rig.

Oh, and I'm using one of the iogear GMP1001W6 USB powerpacks that were on buy.com for $20 a while back for power.

Result: It's sometimes finicky about timing. It makes a difference whether you plug the battery pack first, or the OTG. I think the best config was to plug the OTG, then plug the battery, but... now I can't reproduce the problem. It works either way. But it would get hung up in states waiting for rise or fall, if things didn't go right... Hope this helps those having trouble.