Are there GPS's that will show a speed history of some kind ?

That's called evidence, son...

I want this because I work at dominos part time and two weeks in a row some moron has stopped me and started bitching that I am going too fast even though I was going the speed limit.

The first time is was a curvy road with a 25 mph speed limit. I was going 25 the moron jumps out in front of my car then starts yelling at me telling me I was speeding. I asked him how fast I was going he has no idea but I was speeding.

The second stupid ass was standing there watching his less than 5 year old kid rid a trike around in the middle of the road.

It really pisses my off because I'm the one going 55 on the freeway and these not in my neighborhood jerks are tailgating me.

My Garmin Street Pilot III shows max. speed, and average speed.

It can be calculated after the fact from the track log of many GPS units, but I don't know of any that have this as a built-in.

I have Pocket Copilot Live for Pocket PC. It stores your tracks and you can play them back. There are no controls other than pause, play and playback speed, but the tracks (including speed, heading, lat, long, elevation, UTC time and date) are automatically saved as files. I've attached (part of) one. Now everyone knows where I was yesterday.

-Zeke