See the last page of my thread "All it needs is a battery----" for a photo of a GPS speedo, not cheap but high quality. New to me so I don't have much experience with it yet but like it so far. I have used a couple of the low cost miniature speedos with satisfactory results. My last build has a digital tach/fuel gauge combo but so far I have not been able to get the fuel gauge to work. Non-existent instructions. It looks good though.
Bikes at present:
80 GL1100 Interstate: Now a Cafe Racer called DRAGON WING.
81 GL1100 collecting dust with about 300,000 miles, known as BLACK BEAUTY
2008 (I think) GL1800 Nice bike but as exciting as the family sedan!
76 GL1100 yes, 1100 with 1000 heads and cams, being customized
A fleet of parts bikes awaiting resuscitation or customization or abandonment