I believe someone on this site posted this in another thread, but the leading laser level is not actually a laser.
http://www.trancels.com is the manufacturer of a level that is accurate to +/- 2mm I believe you need click on specialty instruments on this site and then the zip level.
This systems includes what appears to be a wind up tool for extension cords and a wire coming out of it with a small box on the end. you place the large unit (which contains wire) in the middle of the area you want to "shoot" and then take the small box out to a radius of up to 100' or maybe 200' and set it on what you want to shoot.....it give you a direct read out and can be set for many modes. This engineer is a genius that developed this system.....can't explain how it works...but like the salemans that sold me my first Apple IIE said to my question of how does it work....."Do you know how your radio works or your stereo?.....so why do you need to know how the computer works as long as it does what you ask it to." changed my views on a lot of questions I used to ask....although I am still a confesed geek.....
the beauty of this system is that it can be used very easily by one person to estimate a project or install a project. it doesn't need to connect to the base visually like laser so you can be on the other side of your truck and still get a reading....it transports easily and is affordable at around $1000.00 our local vendor offered them to me last fall at around $750.00
This is on my shopping list this spring.......our current laser works fine...in fact it worked the best to set a hung ceiling in our florist five years ago.....bent every wire in the exact place I needed to.
Worth checking out and $1000.00 recovered in less wages and easier measuring will pay for intself in weeks....