I think we're making this more complicated that it needs to be. It seems unlikely that they'll get this right first time, but if they spend years trying to get it right, most of the Teams will be borassic before the cap comes!
Sponsorship bears no relation to the cost of running the Team. It's a commercial decision. Say you get 30 minutes coverage of your name every other weekend in front of 50m people watching around the World. What would that cost by making an advert, and buying TV time on (say) 30 countries? A Team would charge something akin to that, and throw in things like hospitality in Monaco, etc., something you can't get from buying a TV ad. So, if you could get £60m of income this way, and it cost £40m to run the Team, you make £20m profit. This is how the likes of Sir Frank and Ron get to be worth tens of millions.
Manufacturer's make the same calculation - how much value do I get from linking my name with this sport? Ferrari and Mercedes think they get value, Honda now don't. It isn't the most rational business decision, but that's the way it works. The proposed budget cap excludes driver salaries, engines (for 2010) an direct marketing, so go figure how much of a 'cap' that is!
Race Teams are run by owners for a profit, and the sponsorship/income they can get is not related to the cost of running the Team, but the worth of their exposure to the sponsor. So, yes, they may nale a lot more money. but if Stoddard can come fifth in a GP on just £18m a year, why can't someone win on £40m? Oh, yes, I forgot... Brawn GP!
