Change Bed Support Bars with Cables

In over 8 years on various hybrid forums, no one has ever done it, because hybrids like yours were not engineered for it. Yours doesn't have framework on the ends to support the weight from above.
Yours relies on the weight being supported from below, by the trailer's A-frame or the rear bumper area.
The costs required to refab yours, would probably cost as much as buying another one that already had the cable setup.

While I wish my hybrid had them as it would save a little time, in the whole process of setting up, the poles are a not that big a deal. Cables would save maybe 5 minutes of my time. Not having cables would not be a deal breaker for me.

Honestly, if really fast setup/tear down is what you are after, an HTT is probably not for you. There are other tasks with them (much like a pop-up) that are part of being an HTT owner and will require more time than a regular travel trailer. A good example is how you need to make/unmake the beds upon arrival and departure because of the folding bunks. You cant pre-make the beds before leaving so that they are ready to go once you pull into your campsite.

Welcome to the forum!

The newer hybrids have the trailer frames and cables that can support the load/weight. To the best of my understanding the older trailers like yours the trailer frames were designed different where they needed the poles to take the load/weight directly to the trailer frame. Not worth trying to change if you ask me.

Mike