We are currently only offering the kits in the 2-channel version UCD-180s. After CES I'll work on getting all the parts for the UCD-400 2-channel kit in stock. I really only need transformers as everthing else is almost identical. We could offer a single channel one in our chassis but you would only save the price of one module and you would have a rear panel with two inputs and two speaker binding post.
There isn't much in the way of assembly with these kits. It's mostly crimping and wiring the power supply, transformer and modules together via crimp-on faston connectors. The inputs are via a simple slip-on header and you only have to solder to the XLRs, RCAs and the IEC. The next batch of IECs I order will use faston connectors also and the next batch of XLRs will have screw-down tab so that only leaves soldering on the RCAs.
The problem with offering multichannel kits is that we are now building custom power supplies and getting one-off CNCed rear panels for the multichannel amps. It's not a simple bolt together operation and the chassis becomes much more cramped with that many modules. Also.. the UCD400 builds require a fair amount of custom machine work at this time. We can only build up to five of the UCD400 units in our standard chassis because we run out of real estate with larger builds. The UCD-180s we can use up to seven in one 2-U chassis.
Once we have a multichannel power supply PCB and we move to the next production run of chassis I'll probably offer the kits in multichannel configuration. It's going to be several months though because I have to go through my current chassis supply.