Interesting idea. Am using two dry cabinets now but has been thinking of getting just one big one instead. But now that you mention the advantage of having separate controls.
Actually my lenses grew fungus when the humidity was 60% when my Akarui analog meter showed 50% when it was actually 60%. Meters can be inaccurate so it is good to have a separate meter for calibration. Now a little kiasu and setting it at 40-45%.
Question. Why "light seal" the cabi? Doesn't UV light inhibit mold growth and mould grows better in the dark?
http://wiki.answers.com/Q/Dark_help_mold_grow_faster That's why some people recommend bringing the lenses out to use to prevent fungus.