I want to begin by thanking Cristoph Wille for having lent me a hand for my MS GAC blues. See the comment he posted to my previous entry.
I have completed the first pass to gacco.exe (GAC + Paco?). You can find the source code here. I chose to use C/C++ (and a sprinkle of ATL) because my intention is to cut down on interop. Basically my philosophy is that you write code in C# using Mono and period. Being that this is to couple Mono/Gtk# assemblies in the MS GAC and that Microsoft elected to implement their GAC using "COM like" but not fully managed code, I decided to keep this native to Windows and to have the least amount of dependencies possible (gacco.exe is statically linked - 57 KB).
I have to do testing for the Gtk# Runtime installer using gacco.exe. Depending on how well this goes, I may even elect to use gacco.exe and not Microsoft gacutil.exe for the other installers - don't know too early to tell.