As far as I know, there is only 1 bag pattern available for leatherworkers. This is the Kodo Hide Bag, which is a Horde quest.
http://wow.allakhazam.com/db/item.html?witem=5083
My Hunter is a 300 LW, but Alliance, so I have never seen a craftable bag.
The current max slots for tailored bag patterns is the 18 slot bottomless bag. Specialty ones such as herb/enchanting/soulshard go even higher slot wise.
http://wow.allakhazam.com/db/item.html?witem=14510
Personally I would just wait for TBC to be released than get a bottomless bag as they are very expensive. If you must have an 18 slotter go for a supply bag available through AD token turnins or an Onyxia Hide Backpack if your guild does Ony.
Edited, Dec 1st 2006 2:43pm by fnordicus