Apologies, I misunderstood your tuning scheme from your other thread. Looks like you are going for C1, and I first thought C2 which would of course not be a problem.
La Bella has lute strings which are long - I'm not sure of the length because they are more than long enough for me, but a little research should turn up that info, or I will post it later.
The fattest diameter I have seen is .080". At 110 c that should be fat enough for a C1. Ojala... check at the sevenstring dot org site and search for the "zero octave club" and see what those guys are doing in terms of string length and diameters. Although those are mostly electric guitars, the specs are not that different.