This past year we had a laser rangefinder that worked decently. It interfaced to the cRio fairly well and was not that bad to get running. It may be a bit more work this year with the new control system.
As for use and performance, while our drivers and software group never got it fully tuned, it still turned out to be a decent aid to the driver so they could dial in the proper range.
Here is the model we used.. its a little pricy but still falls under the $400 threshold and is Class 1 laser type
http://www.automationdirect.com/adc/...suring/OPT2012