To access some hidden teams, go to Setup and then the Options screen, now hold L a press C-RIGHT, C-LEFT, C-LEFT, C-RIGHT, C-LEFT, C-LEFT, C-RIGHT, C-LEFT, C-LEFT and you'll see a string of zeros at the bottom
of the options screen. The tenth digit is a one though and it enables selection of The Williams Entertainment Canada, USA and 99'er teams.
There's more though, at the Options screen press C-DOWN + R or C-LEFT + R or C-UP + R. A screen will appear where you can change 1's and 0's.
C-DOWN + R: change head size
C-LEFT + R: change body size
C-UP + R: change height
Here are a few examples:
100000: Stocky Players.
010000: Stocky Players, Big Heads.
110000: Stocky Players, Small Heads.
001000: Small Players, Small Announcer.
000100: Large Players, Large Announcer.
000010: Crunched Players, Small Announcer.
000001: Elongated Players, Large Announcer.
110110: Large Players, Small Heads, Large Announcer
010010: Crunched Players, Large Heads, Small Announcer
010101: Large Players, Large Heads, Large Announcer
010001: Elongated Players, Large Heads, Large Announcer