On One Pompino owners...

I am running 113BB with MTB cranks albeit using the granny chaining instead of the middle and outer one and I have a perfect chainline. Hope this helps. Are you running a FD on your setup?

A quick reality-check at the used-parts LBS tells me that MTB cranks of any kind just won't work with a 120-spaced Pomp.
I'm looking at 130BCD Road Doubles now, I should be able to throw together a fairly cheap test setup by finding a decent s/h 53/39 chainset and ditching the 53T ring.
Scored a 43T 130BCD ring for $12, that gives me my 4-tooth difference required for the Dingle cog.
Fingers crossed.