Shellharbour Scuba has a large range of steel cylinders. Tanks are hydro stamped the day of purchase so that you get a full year out of your tank before bringing it in to get tested again.

18L tank 150 CF
15L tank 125 CF
12L tank 100 CF
10.5L tank 85 CF
9L tank 75 CF
7L tank 55 CF
3L tank 25CF

They are din k valves, so you can convert easily between yok and din regs.
300 bar din k valves are also available