You're a Rdm, you can cast Haste, so you can cap recast and cast time Really easily.
AF1 Head and AF2 Body will cap Fast Cast, all that you need from there is 10% gear haste to make up the rest.
Optimally, Dusk Gloves +1 + Speed Belt would be the best combo for space. But a haste belt like Swift, with Dusk Dusk Ledelsens, Dusk Gloves, and Nashira Seraweels would cap, and be cheap. If you don't want to go to Limbus, or can't; Tern set, and Dusk tips are the way to go.
Warlock's Chapeau (Initialization) >>> Zelus Tiara (before the spell completes)
Tiercel Necklace
Duelist's Tabbard
Dusk Gloves +1
Speed Belt (Sonic, Velocious)
Nashira Seraweels
Dusk Ledelsens +1
I think that is as good as it gets unless there's some weird augment piece I don't know about. That brings your casting time down to 50%(cap) and your recasts down 49%. That's almost capped without haste.
Now if you're talking about some kind of melee haste set, then all I'd say is level a more appropriate job lol....