Anyone know if a permanently mounted absence of voltage tester, similar to what is available for low voltage electrical equipment, is available for use on medium voltage metal-clad switchgear?

Given the constraints of NFPA 70E, 120.5 (7), Exceptions No. 1 and 2, is it even possible for a permanently mounted device to satisfy the elements of Exception 1 given that medium voltage absence of voltage testing is typically done with capacitive non-contact testers as described in Exception 2?

My intuition say no, however, if such a device could be developed, it would provide another tool for mitigating the hazards of racking circuit breakers or grounding and testing buckets in switchgear.

I'm sure interested in this as well. Great idea

I don't know if I understood you correctly but do you mean something like this (link inside)? It is pretty common for european MV switch gear to have these. They have to be retested just like the "normal" portable voltage testers. They are built according to IEC 61243-5 (or now IEC 62271-213)

I can't comment on the legal aspects of using them in accordance with NFPA 70E though.