I know that Rushman has one, but don’t know if he just uses it for simple data acquisition (vs. being able to plot out a course and dissect section times).
I believe the middle of the line stuff is sub $1000, maybe even down to the $500 range, but that allows you to plug in and plot the course vs. lateral acceleration. Then if you want to spend more you are talking about adding TPS and braking sensors. I can’t find anything that looks good right now.
http://www.saferacer.com/traqmate-data-acquisition-basic-system.html?productid=554
IMO lap to lap timing is just fine for where I am at now. If later down the road I want to see exactly where I am losing time a GPS system would be a great tool.
If all you are looking for is something to take to Dunnville and get times Longacre’s Hot Lap system is tried and true. And holds twice the number of laps:
http://www.longacreracing.com/catalog/item.asp?id=275&catid=10