I for one have the big r-box, as well as the R-K miner (think it was essentially 4 110gh/s big r-boxes thrown on a tubular heatsink)  essentially that would allow me to upgrade 5 cards, and pretty much triple my entire hash power for less than a new s5 shipped from bitmain...  will have to look for sure but i do believe the heatsink and hash boards in the rk-miner and the big rbox are the same.

* after comparing the 2 it looks like the the r-k miners added a controller (possibly a teensy) on each hashboard,  but all in all same heatsink just 4x as many on the r-k miner and quite possibly the rockminer r-4

big rbox


r-k miner


r-4


so 3 miners utilizing the same form factor and heatsink :-)