I was looking around stadium sites and found this to be interesting, the Aloha Stadium outside of Honolulu. The following GIF shows how the stadium transforms from a football stadium back into a baseball stadium. What I found neat about this is that each formation looks like what it's suppose to be. When you look at some multi-function stadiums they are so big or so accward they become not very functional.
(http://www.law.utulsa.edu/users/larrycurtis/astad.jpg)
(http://www.law.utulsa.edu/users/larrycurtis/bstad.jpg)
(http://www.law.utulsa.edu/users/larrycurtis/stadium.gif)
I thought Tulsa could do something similar to this maybe taking out one of the end zones to be more of what Tulsa needs.
(http://www.law.utulsa.edu/users/larrycurtis/stadium2.gif)
http://www.alohastadium.hawaii.gov/
Just an idea