Why don't you just give them all static IP addresses? That way no dhcp server is involved at all, and the client IP addresses don't change.

It's hard to understand what issue you're trying to work around. Is it the dhcp client that's misbehaving? Do you have more than one dhcp server on your network? Can you configure the one dhcp server on your subnet to give out the same IP address (by mac-address, for example) every time?

-David