Yeah, Obi-Wan didn't seem to have any reaction whatsoever to Dexter mentioning that they're "Cloners"....and Lama Su's dialogue also seems to heavily imply that they've created other clone armies before (although not necesarilly for the Republic). Plus the saberdart in the first place implies that they've probably built weapons for said clones too.
Early in ESB's development, Lando was actually supposed to a clone from a planet of clones (A concept that later sort of wound up in the EU with the Jedi Dorsk)
Back when the EU writers were trying to walk around some of the continuity changes in the films via a few retcons here and there (They incorporated their own mythology over the clone wars that didn't line up 100% with the prequel version), I remember Zahn wrote a short story about the Spaarti cylinders from his trilogy being a sort of alternative method that Palpatine sort of had as a backup; likewise there was a story arc in the Republic comics about the Seperatists building clones of their own (Via the "Nikto" aliens seen in ROTJ).