Here is a link to intank.com filter mods very cool. Looks like it would go for up to 30 gallon or so. http://shop.mediabaskets.com/AquaClear-110-Media-Basket-Fits-Tunze-9002-AC110MRX.htm
That looks like it would be awesome for a QT! You could put a bunch of ceramic media in there and still have room to run carbon if you needed to.