Maybe I am confused but this looks like it has ten outs on the back, not an additional ten inputs. Am I wrong? Do you have one of these in your studio?
You could look at the MOTU 16A. No pre’s, with 16 ins and 16 outs. I have not used that particular one, but I have used their 828es, which sounded great, had rock-solid drivers, and hardly any latency running through thunderbolt on my Mac. Also is rackmount as you requested.
On my 828es, the conversion was great. No complaints really. Again, I haven’t used the 16A, but speaking about the 828es, my experience has been very positive.
Behringer XR18 has 18 inputs and is dirt cheap… yes it is not 1U but there are not many interfaces with more than 8 inputs, at least for a decent price… usually they have ADAT for more INs and OUTs…
I have used an Antelope Zen Studio the last 6 years. Its a 12 preamp + 8 converter in and 8 out+ a stereo master. Its great and the vast I/O makes it very flexible.
I just upgraded to an Orion 32, its only converter I/O cause I got a analog mixer that I use as my preamps.