I fully expect that Unicat design and build their own slide out mechanisms, as they do with many of the other components they use.
When you have a budget that supports buying a Unicat, pretty much anything is possible.
An "out of the box" RV slideout unit I expect is not designed for much in the way of off road conditions. However, I figure that if you did want to fit a one of these, it would be possible to make it strong enough.
The first thing I would add would be some securing clamps on the inside, that held the slideout tightly against the seals and camper body. This would take the job of securing the slideout away from the actual slide mechanism.
A hard sided poptop, which is what I intend to build, is a different story entirely. You have gravity on your side, helping to maintain the contact between the roof and the camper.
That said... I will likely preload the roof/camper joint with a spring mechanism in the lifting/lowering actuators.