i'd totally be down for a helix / spiral pattern. i was thinking along the lines of: base of the glass tip [the part that goes into the hose] be similar to the nammor/razan, like either a square or slightly rounded base. then from that, it splits into 2 pathways that spiral upwards around each other, then connect together to form the tip.
then for coloring, either just color the base + tip and leave the spiral clear [it'd be fun to just watch the smoke go through the tip] OR have all of it mostly clear with a few thin colored stripes running up and down..
very intricate, very complicated, but if it's durable and beautiful, i'd prob pay up to $20 or $25 for it.
also a suggestion - from watching the vid, it seems like the tip slides into place pretty easily, and also comes out pretty easily. maybe you can wrap the base of the tip in electrical tape or a thin foam-tape so that it would friction fit more securely into the hose?
other than that they look absolutely great and really look forward to seeing you take orders for them