I was looking for some of these also, and it looks like I have found the perfect thing,
http://www.shokaifareast.com/Product...ail_guided.htm
100k Ohm, linear slide with 100mm of travel. However I see no way to order from their site~
I emailed them, hopefully I will find a way to order quickly. or maybe a team around the area they are located could pick some up for us. If anyone finds a way to order from them, it would be a ton of help.