I think that Count Dooku/Darth Tyrannus “borrowed” the late Jedi Master Sifo Dyas’ name either just prior to or shortly after his demise in order to give credibility to the claim to the Kaminos (who actually seemed to be nice people ) that he was ordering up the clone army for the Republic. When talking to Jenga Fett, there was no real need to style himself a representative of the Good Guys, since Fett himself was a nasty sort of character and was just in it for the cash.
I’m thinking of two possibilities on ways the Clone Wars could turn.
First of all, though clones are, um, bred to be docile, the original for this particular army was Jenga Fett, bounty hunter, assassin and all around not very nice guy. They probably have a lot of his basic personality traits. Also, it was a Jedi who killed their “father”. I think that it is possible that D. Sidious, or one of his agents, could persuade this clone army that they’re taking orders from the wrong guys, possibly offer them a better deal, and turn them against the Jedi and the Republic. Alternately, as the de facto head of the Republic, Palpatine/Sidious could legitimately claim control of the army and use the clones to solidify his postion as dictator (which would be the logical next step after getting “emergency powers”) and then declare himself Emperor.
Another scenario might be that, since cloning seems to be commonplace enough as to not raise eyebrows, perhaps another planetary corporate body, which may not be as careful about selecting their customers as the Kaminos, might have an army of clones baking that Dooku/Tyrannus, or some other “opposition” leader, could use to further the war (assuming that the battle droid factory on (insert name of planet I can’t remember) is not left operational for too much longer, or that clones prove so superior to battle droids that the use of droids falls by the wayside. Then you’ve got clones fighting on both sides. What a mess that would be…
Third scenario- clones are not as docile as we thought. Remember, the Kamino PM said they can think creatively. With the smarts, they might, if left to their own devices for too long, get the idea that they’ve been used to further the ambitions and aims of others, with no real benefit to themselves and start digging in their heels, eventually turning against their masters.
Also, I hold with the idea that cloning isn’t illegal, and if it is, Kamino is outside the jurisdiction of the Republic, and a legal loophole might allow for the importation of the clones once they’re already cooked. It seemed the Kaminos weren’t really keeping their operation a big secret. They were quite ready to assume that a Jedi dropping by unannounced was simply checking on the progress of an army ordered by a “Jedi Master” years before. They didn’t seem bothered by the fact that Obi-Wan obviously didn’t know a lot about who ordered the manufacture of the army, or why. They simply answered his questions and showed him the goods.