I think that looks pretty neat. Each CMA is sitting right behind its PE1950 and just takes 1U (although the power sockets on the left are a bit tight). A Sierra would just be a 4U hole in that. I'd surprised if that mix actually occurred in the real world though!

I think though, if you've got the miner in a DC and it need a hardware power cycle you've got more problems than just reaching into the back of the rack (you've actually got to go to the DC or pay some dude to do it! And it raises concerns over the equipment's reliability). And anyway, DC costs are going to bite into the miserable ROI. Who would even think of doing that unless they had some free space?