Keep in mind they're looking at producing sub 65nm chips. Even at 65nm a good design could let you get to at least 2GHz+ (AMD's Phenom series for example reached at least 2.6GHz on 65nm).
You can get to 2Ghz + at 130nm, which is what the first gen Athlon64's were, later dropping down to 90nm. The problem is not getting to the speed, but in how much power it takes to get you there. Which is one of the reasons why Intel using 45nm (and later 32nm) for their Core iX series have significantly lower power requirements than current AMD parts as well as better performance.
For now it's all speculation, but it'll be fun to see where it goes... If they succeed it'll be a *major* upset of the chip business, since so much of it now is centered around a dependency on this small number of multi-billion dollar fabs and a massive barrier of entry for small chip design companies. If that changes you're likely to see tons of new startups try their hand at designing everything from new CPU's to very specialized ASICs for specific purposes.
Could certainly set the cat among the pigeons.
