Need suggestions for budget proposal

If you "generally charge $40/hr" then start with what you can identify about the project that correlates to what you "generally accomplish for that $40" - in other words, what do you typically finish in that hour of work?

You also need to consider whether offering the potential client a slightly lower price (with the likelihood of a lot of future work) is a worthwhile cost exchange. The upside is that you get a lot of business (hopefully) for a long time (also hopefully); the downside is that the client may expect you to reduce your costs/prices because of the volume of long-term work. And you are already starting on a lower side of your "general" price scale.

Why don't you approach the work from a tiered perspective:

• Standard rate: $40 - Review the PPT content - Estimated time: 2 hours
• Translate content to storyboard: Estimated time: ____ hours ("for this work, I will charge a flat rate of....") Note: If your "general" rate is $40/hr, that works out to $320/8-hour day. So the content-to-storyboard work could be $275 (say) or something other than a full-day rate. You get to decide.
• For the greater design work - again, you get to decide. But you could decide after reviewing the content and storyboarding it that you really do not want the project. So propose a "Rolls-Royce" rate (or as Daffy Duck once said, "If money is no object, here are my very unreasonable rates!"), and charge a rate that will basically tell the client, "I will do the work but you are going to pay a lot for this."

By coming back with a tiered proposal, you are neither tying yourself to the client and the work, nor are you undercutting your "general" rates just to keep an open client pipeline. 

Good luck -