First, although you asked us not to say so, I have to just clarify that it is quite simply a fact that you cannot be guaranteed to be number on Google for any ORGANIC search results for a keyword term EVER.
I only tell you this because I want to stress that this is what MAKES Google such a great thing, as it levels the playing field, more or less. Nike cannot be number one anymore than Joe's Shoes could be (organically). Google's algorithm for ranking pages is complex and ever-changing (with new changes ever month). Anyone saying they can gaurantee a number one spot for ORGANIC search results is quite simply lying, because the algorithm doesn't work that way. It displays different results based on geographic area, time of day, website traffic, etc.
That said, I can guarantee you two things for my 1k quote (within a 30-60 day time period, as that is how long it can take for changes to REALLY fully take effect).
1. A number one spot on paid results that show up above the organic results at the top of the page (this is simply a matter of bidding correctly on the keyword terms to be sure you rank number one all the time).
2. A top 10 (first page results) Google rank. I can guarantee that through my work, you will be on the first page of a Google search. Depending on your keywords, you could be as high as the top 5 results, which everyone covets. Also, note that the 2nd and 3rd spot often get just as much traffic, even sometimes more, than the first spot.
Good luck with your project, and hopefully I was able to shed some light on this for you, even if you choose to go with someone else. Please don't be taken for a ride by someone 100% promising a number one search result every time, unless they work for Google and have a way to hack into the system and cheat.