There's plenty! I know the other big one on the West Side is Siciliano's Siciliano's Cup competition each May. They usually cap at around 250 entries and there is enough interest to make it cap out. I think they start gearing up for that in February.
I don't know much about the Metro Detroit are, but there's lots of smaller competitions all over the place. I'd suggest searching for homebrew clubs and sending emails asking about their upcoming comps, or asking if they know of them.
Not all clubs will submit the information, but you might also check out the BJCP website and see if there are any comps listed there.
Our club just judged our fist competition last week, and I know of probably 3-4 off the top of my head that are pretty local to me. They are out there, you just have to search.