In the realm of custom work, fixed prices are dangerous ground. It puts you in a position to either say "no" or ask for more money when a project has extra needs, and that's never a comfortable situation to be in.

You said yourself that speaking to a lead is the best way to make a sale. I'd echo that.

I'd also argue that letting potential clients know that custom animation is complex, and prices will vary based on their needs (which require a conversation to determine), is a great way to start out the relationship honestly.

If you're worried about lack of a stated price being a deterrent: people who shop on price without any eye toward quality are not the clients you want. If your portfolio is good, a serious lead will contact you and several other shops to get an idea of your approach and pricing. The BEST clients will hire the team that makes the best initial impression and shows the highest level of understanding the project; price will be a secondary consideration.

My general stance is: if you're selling on price, you're doing it wrong.

If you're selling custom work, sell custom work. Don't try to shoehorn custom work into a prepackaged box; it'll turn off high-end customers and attract the deal-seeking, high-hassle clients that are less fun/lucrative.

Good luck!