You can unlock a Cheat called 'Giant Stetson Mode!' then enable it in the secrets menu!
Go to the Undercity. Go to the ledge where two snipers are awaiting your disposal. Jump to the ledge on the right, climb onto the next ledge, and look for the curved U-shaped pipe. Jump to it and the "Secret Activated" message will appear.
N64 & Dreamcast Location:Edit
Not avialible on these consoles