What exactly are you looking for, something to let a gaucho slide out? I would think that type of slide would need to be able to handle some weight. These table slides are designed to let a table open up in the middle and let you put one or two leaves in but they dont have any capability to support a weight unless they are supported underneath. If you are looking for a slide that will support some weight, take a look at the 200 lb full extension slides from Lee Valley. I've used a set of these in my workshop for moving a heavy radial arm saw out from the table and they function well. They are fairly inexpensive, even the 36" slides are around 50 bucks.
200 lb Slides - Lee Valley Tools
Now if I'm missing the point of why you want to use table slides on a gaucho, then please correct me.