i have only seen HO
T5's as short as 24", so if you dont want the overhang, you may want to consider going with
PC lighting and placing your LPS's up high in the tank. OR you could always run 1
metal halide pendant type fixture on a tank that small. i would say a 175w should do just fine. you will probably have to buy a clip on type fan to dissipate the heat from the halide though.
MyReefShop :: Ballasts :: Coralife Aqualight Advanced Tank-Mount