The bids for the final have already been submitted and the results should be known before the semi-finals are played. Before, it was just a matter of who put the most money on the table in a blind bidding process. But since the USSF wants a bigger slice of gameday revenue, now a portion of the projected ticket sales is also considered as a part of the bid. If you're uncertain of what that means, here's a translation: USSF saw that Seattle drew over 30,000 for the final--a feat not to oft to happen and said "hmmmm, I think I'll have me some of that". it would be hard for anyone to keep up with Seattle's money to begin with, but when you throw in this new factor, it is virtually a lock that they will host the final, should they progress through the semi-final round past Dallas.
Should Dallas make it through and the Fire win, I think it will be a very tight race to host. While Dallas has traditionally been VERY poor in attendance, they have been good of late on the field and in the stands--this could mean that the ownership would see value in having a cup final played at home in front of a team and crowd that is growing in size and confidence. Whereas in Chicago, the dwindling attendance (both in league and USOC) during this season and an absentee owner who is more concerned with throwing great parties (and believe me, the Fire Foundation's "White Party" was AMAZING), and a faultering team with only the USOC to play for....well, the outlook for the owner to bid big isn't really there. All we can do is hope that A. we get past Richmond (and they've been really good in their division recently), B. Dallas win and we outbid them to host, or C. keep looking for cheap airfare out to the west coast.........then it's up to the team from there.