Thanks EuropeanDistrib and Directorik. No, don't worry, I'm not planning on doing this myself, I just asked because I know two separate producers who did just that and I don't think either case turned out well. Neither producer was terribly forthcoming with me about what exactly happened, but one project never got made. The other project did get made, but the producer was being sued by agency of the first actor they had made an offer/deposit to. The reason? The producer had revoked the offer to the first actor after paying deposit and offered the role to a higher-level actor who expressed interest (and ended doing the part). So first actor's agency was suing producer for remainder of offer. Not sure if there would have been a suit if the film had simply not been able to finish raising funds. I imagine the first actor was pissed and insulted and wanted some payback.
I do understand how trying to raise funds or pre-sell on one actor's name alone when he/she is already signed is risky for that actor's career. But what's the order then? Would you first go to a sales agent or distro and say "If I get actor X and Y for this here script, will you give me a pre-sale contract?" If the answer is yes, you call the actors' reps and say that you have a production is fully funded and we would like to make an offer to your clients for this much money. Once you bank your pre-sales you can certainly at least cover the actors' 10 percent deposit, and you are in a decent position to go look for equity and of course get some tax credits. Is that a decent blueprint?