You can get power for a meter from your headlight bucket, but it will read a little low.
When a device draws a lot of amps through a small wire, the voltage decreases. That's why many people recommend adding a relay for powering the headlight so the light bulb gets full voltage. You may also want your meter to get full voltage.
I use a pair of wires going right back to my battery, with a fuse at the positive terminal of the bat. By running a new 10AWG pair, I can get an accurate reading from a meter and still use 5A on that wire for a heated jacket.
It would be easier to use a wire in the headlight bucket, compare that to a reading at the battery with a multi-meter, and just remember that your display is 1/4 or 1/2 volt low.
No pic of the face of the meter on my 750. The meter was just behind the brake fluid reservoir:
On a thumper:
Previous arrangement on thumper:
This last is sold as a "5-fnction meter" but beware. It's not at all waterproof. Mine was accurate about 95% of the time but it was sometimes hard to tell if it was OK or not.
I currently get simple 2-wire meters from MPJA:
http://www.mpja.com/Mini-3-Digit-LED-Battery-meter-Input-Powered-Red/productinfo/19598%20ME/ This is the same as the one currently on my thumper.
The one on my 750 was larger and I had to build a 5V power supply to run the meter. These little ones are simple 2-wire meters -- self powering -- all you need to do is enclose it.
I'm sure someone else has more finished solutions.
