Are there any products out there that are geared towards campus-wide (IDF-level) OOBM?

There are a ton of out of band management products there today, however, I've yet to find out that is suited for a campus-wide out of band management solution.

I realize you could always build out a separate out of band network with fiber going to terminal servers in each IDF, but not everyone has fiber available. You could transmit serial connections directly over Cat5, but the distance is limited. You could always put an OpenGear OOBM in each IDF with a POTS or cellular connection, but that has problems of its own (cellular coverage, opex for dozens of cellular, opex for dozens of POTS and/or having to operate a legacy PBX).

What if there was a central OOBM device in the MDF that connected to console servers in each IDF using DSL, instead of ethernet, over voice-grade cabling? Admittedly, I don't know much about how DSL is implemented, but couldn't someone conceivably build an OOBM device that doubles as a DSLAM and a DHCP server? This way you wouldn't have to buy transceivers or run additional fiber, but you'd still be able to get some of the distance benefits.

Is there some reason why this would never work? Or is there in fact a product that does exactly what I just described/accomplishes the same goals?