This is a variation on the original Rocket Display Tree which replaces the individual pins with a 1" dowel that runs through the entire tree. I received a few comments that the original pieces were not tight enough on printed on some printers and the tree was leaning over.

This one will solve that problem. For testing, I used a 1" x 48" dowel I bought at Home Depot for $4 and change; Link here

This provides significantly more rigidity, and you should be able to double the height as long as you manage the weight distribution.