after seeing the min-etune on gibson's website, i tried to find a variant for bass, with no success. does anyone know if these exist, or if robot tuners would even be able to withstand the higher tension?
Tension isn't an issue. They just haven't done the tooling to make a version that would work with bass.
There's not nearly the market for bass robot tuning. Both in terms of absolute numbers and the fact that tuning on basses is generally more stable than guitars because of string construction, how they're played, etc.