There's lots of nice stuff in that nixie thread! I think the Fluke 8120A looks like the most practical general use nixie DMM, considering the ranges it has. I do like the HP units, but the ones I've seen have fewer ranges, and are much larger rack mount devices.
Paul, I would very much appreciate the 8120A service manual, only if it's not too much trouble. How much did you get your 8120A for, if you don't mind sharing? Not sure what I should expect to be paying.
Thanks to everyone for the input.