Development Contracts

I'm working on an estimate for a client who wants to put his down payment in escrow. Normally I indicate that 1/3 of the development cost is paid up front so that I can cover expenses involved in purchasing domains, hosting, ssl certs, etc. In this case the money for expenses will be tied up in escrow until the project is done, so I would be required to float expenses on my own feeble income. If for whatever reason, something fails, and escrow is paid back to the client I would be out of expenses.

Does anyone have experience with these situations that would be willing to share some advice or contract verbiage?