I was just looking too. But also I went to a local topper shop in town 3 years ago and they had a good few options available. I wanted a hi-top type and they could get the ARE MX one in the hi-top for the double cab 5ft bed. I didnt pull the trigger on it then. Now i've been looking again a bit, but only online so far and on ARE site, they do not show the hi-top available, but they show a couple of the cab-height ones still available. Seems about the same for the snugtop and others as well. So if you are good with a cab-height one and really want one (new ones are a bit pricey $$$$) then you should find a local dealer and talk to them. The place here also carries a selection of used tops, but they are mostly for your big three fullsize trucks--they had nothing for my Tacoma when i went there. Could be worth a shot.
Otherwise, keep your eye on craigslist and other classifieds near your area.