Well the 9x25Dillon is a unique round, Underwood Ammo and Double Tap Ammo are the only commercial loadings that I know of...Both would be online purchases...
At the moment Underwood was only showing 125gr bullets where as DT has several bullet weights to choose from.
If you decide not to handload save you brass and keep me in mind...because this cartridge case is subjected to very high pressures, they are prone to failures. So I'm always needing some extra brass. Feel free to PM me if you have any further questions about the 9x25 Dillons.
If you wish to reload for this cartridge I would suggest you read everything posted here; http://glocktalk.com/forums/showthread.php?t=228796
Dillon makes the dies that will make the properly necked cartridge cases but they are expensive. They consist of the Sizer Die which has two carbide sections one for the 10mm and one for the 9mm sections. The set also contains the Seater die and Taper Crimp, these have a double ended seater plug that is shaped for Turncated Cone & Round nose bullet profiles. You will still need a 9mm sized neck expander die (I use either my RCBS 9mm or my LEE 357Sig expander) to uniform the necks to accept the bullets without crushing the neck section but still allow good neck tension.