Hi all - first post so go easy on me!

Have a project that requires me to source really long (for me) linear actuators - basically two units that are 8 meters long and to be driven together via servo drive. preferably the drive motor is external to the gantry (e.g. no omega drives etc).

The application is not CNC, though there is force opposing motion outside of friction/mass/etc. These will move a gantry of some 30kg mass. Accuracy (+/-0.1mm) and repeatability are important. speed isn't really so - 0.5m/s (around 1200ipm) would be great though i'd be happy with 300ipm.

Our local linear motion suppliers are having minor heart attacks over this, so I thought I'd canvas the project here first. I know that they'll need to be belt driven units and that tension is going to be a challenge (as is a relaiable position feedback source).

Has anyone out there built their own? Any comments/thoughts/references?
Success stories/failures?

Keen to hear your feedback (and hope I've posted this in the right forum...)