There's at least one set of M1 based Translators knocking about, which not only translate but also have a gennie to provide full hotel power including power operated doors. Although they are air braked vice vac braked, the concept is already accepted. Not that uncommon to have a generator car, some test trains also have gennie cars.
All the info for gennie cars is established, just needs the right attitude.
To be honest, modern gen sets are so good, this shouldn't be an issue. Modern gen set and modern industrial cabling, very robust and not too costly. Nor is the "approval" an issue, in the fairly recent past I had some involvement with a test train equipped like this and it was highly effective and economical to achieve.
TPO