well, I can imagine some of the quirky big name artists wanting such, but in my world I don't think it would be feasible, especially since real estate is at such a premium in the tiny, packed places I work!
There is no world in which it is feasible because:
a) A $200, one rack space unit can sound better and have much more sophisticated options. Ya know that "pre-delay" function in your digital reverb plate set-up? It's not there on the analog plate. Back in the 70's and 80's when using a plate in the studio, to get "pre-delay", we had to send the signal to a dedicated two-track reel-to-reel recorder, using the distance between the record and play heads as the delay. The length of delay was determined by the speed of your (hopefully) variable speed two-track. The other source of analog delay was the Cooper Time Cube, which had two channels at 14ms and 16ms.
b) Who wants to load in/out night after night?
c) As stated by JR, there's a noise issue. There are pickups/microphones attached to the plate which are sensitive to noise around the unit..
Of course, all of this logic goes out the window when some tired old rocker decides that the EMT sounds better than the digital unit he'd been using before
