I understand what you're saying now.
Buying up domains and working on top 3 spots before launch sounds like a great idea. The amount of time you put into it and the investment financially will be relatively small so its worth giving this a shot. If a lot of traffic is generated on launch then you win, if not, you still didn't lose much time and investment.
I haven't used anyone on here for XRumer blasts, but I did get a really cheap and successful submission from 'nufa' at digitalpoint forums, see if he's still offering his service.
You might also consider ranking a bunch of web 2.0 sites as well, like squidoo, hubpages, wordpress. Get all the good keyword properties (e.g: squidoo.com/yourkeyword) before others do, prevent future competition. However, make sure you don't use XRumer on these, especially squidoo, squidoo never fails to shut down my pages once I send them links using XRumer.
And as said before, make sure every site/page you build has unique content. You may also consider buying your domains with private registration and putting them on seperate I.Ps, I'm not sure how keen Google will be to rank all your domains in the top 3 if it knows they're all owned by one person. Maybe others could comment on this?