"Travel" hoop made of PEX tubing.
PEX and similar plastic water pipe can be used to medium to large circular hoops. They can even be used to make segmented travel hoops that can be easily assembled and disassembled. They can be used bare or can be covered to increase capacity.
A ribbed sleeve can be easily added to any size hoop and holds a bit more juice than without.
Covering PEX wands. Even without a covering, a PEX hoop can work quite well. As with wire hoops, wrapping a PEX hoop with twine or similar material can significantly increase the number of bubbles that can be blown with a dip. Ribbed plastic tubing can also be used to cover the hoop.