Ok, so i'm late to the party for posting this up, but I was busy during the holidays with the family. Anyways, in case you missed it, here's a demo from Edelkrone's unique SliderPlus+. It's a 1ft slider (to fit your travel bags), that travels 2ft. Doesn't sound like very much sliding movement, but as with any tool, you just have to be creative about what you're using it for. There are still questions about how smooth the slider really is when operated by hand, but with a motorized adapter on the way, this slider can be very consistent with movements.

Edelkrone Slider Plus Retractable 2ft Slider