Dave,
You might check with a local laminate supplier (formica, wilsonart, etc.) In a previous life we installed laminate tops for big box stores, and we used a product called seam seal. Not the caulk, but a color matched filler for the laminate joints. It came in a gazillion colors, and hardened like a rock. I'll look through some old records and see if I can find some info, but it should be pretty easy for you to find locally.
Dan