I know this isn't exactly what you are looking for, but.... This game needs more Cowbell!
http://www.antonline.com/p_90071200-GP_337064.htm#
This one is cheap, good size for Vex, stackable (though likely unstable after a few in height), and it has a nice open loop on top. They are also easy to paint for point differentiators, and can be useful/annoying once the season is over.