Anyone replace Formica counters with solid surface?

Besides the box stores, you could try cabinetmakers. A lot of them are certified for solid surface tops.

Personally, even if I could buy the tops, I would go with plastic laminate and make them myself. To me, the laminate is less maintenance and that is a plus. I have 18 year old tops that I made in our kitchen and there is absolutely nothing wrong with them.

Good luck with whichever you go with.