i dont remember the vid saying only 3 places but i wouldn't be surprised. I wonder if we can buy all 3...my main guy has 800k that needs spending

You can build up to three homes (Gstaff said that on the blog).
I'm hoping you can build on various plots of land throughout the holds, even if you're limited to one home per hold, but I think it's more likely that they'll take a "One-Size Fits All" approach to your home as far as where you can build.
A necromancer who wants to be left alone? You'll build right here!
A trader who has regular contact with people? You'll build in the exact same spot!
Never mind if you're character would be likely to build in a secluded area or right in the town. You get that one plot in Falkreath, and nothing else.
I really hope that isn't the case, but I'm not getting my hopes up.