There is no choice of suspension type - the 5.0TA has beam axles and leaf springs (Dexter D35), and the rest of the models have rubber-sprung "torsion" type independent arms (Dexter Torflex #10). As Jim said, the leaf-spring setup was chosen because it is easy to switch it between two different heights (about 4" difference) to suit different tow vehicles - matching height is much more important with a fifth-wheel, since the trailer must clear the truck box.
It would be a problem to offer a choice between these designs, because the mounting to the frame is different, and because there would potentially be interference with other components (such as water tanks) under the trailer. Switching from Torflex to leaf springs would generally be considered a downgrade.
Escape has offered a "high lift" Torflex suspension for some models in the past, but it is not currently listed. A lift (of about 2 inches) should be practical by inserting appropriately designed spacers, but that would need to be confirmed with Escape.