Well, I finally finished up the wiring on the Moto Linguini/Savage project. Used a Motogadget under the tank and the Motogadget M-Button in the headlight bucket. I started the project years ago, and at the time only the first Gen Motogadget was available. The newer one is even sexier.
Basically, this provides relays and circuit breakers for everything, as well as providing some interesting electronic tricks (one wire to the tail/brake light, different flasher modes, etc).
The M-Button takes all the info from all the handlebar switches and sends it to the Gadget with one skinny green wire. Much tidier wiring. You'll see the green wire on the lower row of the box. I managed to break the rear brake light switch, so that wire is disconnected. Other than that, it all works brilliantly. Much less wiring than stock. And the stock stuff was trashed anyway.
Highly recommend for a major custom build. Maybe not so much for a minor tart-up.

Well, now I'm going to have to start calling you Mr. Clean!

Thanks Ohio!

Edub,
I got most of my stuff from Revivial Cycles. Good website, lots of good How To vids.
That unit was in the low $300s. Replaced by a new one with more cool stuff. Offered in two versions, low $300s, and low $400s. The M-Button was maybe $80? And I bought their wiring kit.
Did all the work myself. Lots of head scratching.
Makes the wiring so much cleaner!

Hooray for more m.unit users! It really does make the rats nest of stock wiring manageable. Was the m.button worth it? Planning on running another m.unit on my wifes bike and the m.button is tempting.

I see something in my future.

If you have a relatively stock bike and a good harness, I'd leave it alone. My bike was a total basket case and became a very modified cafe racer. Stock harness was not an option.

Batman,
The M-Unit is under $400 for the high zoot one, and the basic one is a little over $300. So, not over $500 as you said.
Having said that, as I stated, if a bike is basically stock and you have a decent harness, it prob doesn't make sense to go with the Gadget.
$500 means very different things to different people. I work on people's bikes all the time who are very well off. $500 to make the wiring this neat and smart is no big deal to them. Two of the bikes in the garage I work at put $5K in carbon fiber wheels on their Ducatis last year.
I'd be afraid to add up how much $ I have tied up in my Savage project. And that's with me doing all the labor and fabrication. The Gadget stuff was a tiny part of the project cost, and well worth it.

To be clear, I was not judging the cost or use of the m-unit.  I think that it's appropriate for some, just as the stock harness works fine for others.