It's a fairly safe assumption that both AMD and Intel have a good idea what is going on with the other company, especially when it comes to products that are due to see the light of day soon. This means that Intel probably has a very good idea of what to expect from AMD quad-core CPUs that are due out in few short months. So what does Intel think of Barcelona? Well, according to this DailyTech article, it seems that Intel has abandoned a 2.13GHz quad-core CPU and is now planning on bumping their existing mid-high end 2.4GHz chip down in price, possibly even cheaper than they had planned on for the 2.13GHz.
If all this ends up coming about the way DailyTech says it might, then it would seem reasonable to posit that there might be at least one more high-performance quad-core to be released prior to AMD announcing the availability of Barcelona.