You mean tuning the bass ADGC, like the top 4 strings of a 6-string? If so, that's generally called tenor-bass tuning, and there are a handfull of people who do it.
If you mean taking a C string and tuning it down to G, just using it like a really light gauge string, then I don't know many people who do that. On my fretless Kinal Acoustic I use an ADGC set and tune it down to standard EADG. Works great for me
