Hi Ian,
Yes, several of us have indeed made our own looms - some real good ones (do a forum search and you'll see some very good ones) and some like mine.
Everybody has their own ideas, needs, background and all the rest when they decide to make their own. I make mine based on quite a few (rally / offroad) vehicles, boats, aircraft and campers. They're all different. So read, look, ask yourself what it is you want to achieve and make a good honest inventory of your needs before you start doing the sums. Good quality cables, crimp tools, strippers, (multi) connectors, etc. all add up. I've just done the 88"Hybrid and over 260 mtrs. of cable in there somewhere.....
With my looms, colours mean nothing. Everything has been labelled with a number and the database will tell you what it is, where it is located and where it is connected to. With over 590 labels in the database you'll need it. But I'm know for my overkill. đ
Have Fun !