Jamye, every point that MichaelB made is excellent and right on target.
I`ll piggyback on his point. I would focus more on the long term royalty stream. I would use the fact that you have 30 - 40 more designs in your bag as leverage. Possibly even to ramp up the % paid based on other successful designs that you have provided them.
Best of success!
Jamye, if you do have other options and they will not offer you an agreement that you feel is a win-win, then do as nhgnikole said, and walk to the next one.
But if this company is the only real option, and this is becoming a deal breaker, maybe you could tailor your needed upfront money as an advance against royalties.
If the deal goes south and no other real licencing options, what next?