Many of today's "hybrid" trailers have shed the canvas but keep the weight advantages of the "hybrid design". While the canvas types are still available, many have incorporated "hardwall technology" into the bed slides. These trailers are just as secure and just as comfortable as their "hardwall counterparts"....
One example of how living space is maximized by "bed slides" is the Outback brand. You can see some photos of one of the Outback floorplans in this link:
https://www.rvtrader.com/listing/201...URS-5000970497 Note that there is an obvious "lack of canvas" in the bed slide. Other brands, other companies beside Keystone produce "hybrid trailers without canvas".
There are alternatives available, don't give up just yet......