The usual suspects would be Carnivale, Nacional 27, Topo and Sushi Samba. They all have good ceviche offerings but none that blow me away. For that I go to La Mar in San Francisco. They're an upscale Peruvian chain just breaking into the US market.
Oh my god, I went to La Mar too and I would live there if I could. I'm not betting they'd open around out parts anytime soon though... our fresh seafood offerings don't quite offer the same level as sf does. Unless they want to make lakefish ceviche.... I wonder if that would be any good?
"Unless they want to make lakefish ceviche.... I wonder if that would be any good?"
I've played around with ceviches a bit. Sea bass - clearly not a lakefish - makes for a surpisingly good one but it will get rubbery if it "cures" too long (likely why you never see it on menus).
As far as local restaurant options go, I've been to a couple of the Peruvian places listed below and I'll stick with my suggestions above. Better to go to a place that does fish well than to go to an "authentic" Peruvian place where the fish quality is hit-or-miss.
Years ago I happened into a place in LA (the name has long since been forgotten) that had a ceviche bar - about a half dozen options. It was more or less a prix fixe brunch buffet and I easily consumed my weight in ceviche alone. Sadly never found another place like that again.
Metromix lists six Peruvian restaurants in Chicago:
Ay Ay Picante Peruvian Cuisine - 4569 N. Elston Ave. - Chicago (North Park)
Machu Picchu - 3856 N. Ashland Ave. - Chicago (Lakeview)
Taste of Peru - 6545 N. Clark St. - Chicago (Rogers Park)
Fina Estampa - 2937 W. Montrose Ave. - Chicago (Irving Park / Avondale)
D'Candela - 4053 N. Kedzie Ave. - Chicago (Irving Park / Avondale)
Rios D' Sudamerica - 2010 W. Armitage Ave. - Chicago (Bucktown/Wicker Park)
I haven't been to any of these, but you might want to check out their menus, either on Metromix ( http://chicago.metromix.com ), on Menupages ( http://chicago.menupages.com ), or on their own websites.