This is exactly what I'm planning to do when the time comes to wire up the motor and MS. I want to use a single heavier gauge ground wire (probably like 10 or 12 awg) and remove patches of insulation, solder in jumpers to all the grounds on the motor, then seal the connections up with good heat shrink.
The 12 gauge wire is more for mechanical strength than for conductance, I figure that it will take a beating if I'm constantly stripping and soldering to it, and it needs to be fairly tough.
The DB37 side connection can be done simply by stripping off enough of the ground wire insulation, laying it over or wrapping it around each MS grounded DB37 pin, then soldering it.
I would also like to see pictures of people's wiring harnesses. Especially if they took lots of time to do a nice clean job. There are not a lot of MS wiring harness pictures that I have seen on the various forums in which I lurk.
I don't know where it is, but there is a picture of an L28 Z car (perhaps BRAAP's?) that has a pretty clean looking wiring harness. What I like specifically about this car is that the injectors were wired in such a way that the wire fit inside a very small split loom and stretched in a very straight line across the tops of the injectors. It came out looking very clean.