Back from Milwaukee (a little earlier than expected) so here is my report, and thanks much to TBOO and Kent for the fine leads (with addresses, yet).
Went to Tres Hermanos, got the sopa siete mares ("seven seas soup")and was thunderstruck by the goodness. I have had seafood soups at Mexican restaurants in Chicago a few times before, but I think the rendition as doled out by Tres Hermanos is simply the best. HUGE portion in a huge bowl (tureen?), impressively served up so that heads turned in the restaurant. Broth is thin but fully flavored, quite hot & spicy and heady with herbal flavor. Two crab claws hanging over the side; inside, two good-sized fish fillets, a couple of mussels in their shells, about 8 medium large shrimp, and oodles of cut-up octopus, tender-chewy. On the top, a medium-small lobster tail. Served on the side, limes (for squirting onto soup) and chopped onion and cilantro (you may have to ask for this) for added herbal zip. Flour tortillas, of course (but who can think about eating these when confronted by the gigantic soup?) The price--$13.95. (Oh yeah, before I forget, some nice vegetables in the soup as well--carrot pieces, cut-up red potatoes, fresh green beans.) And, none of it tasted/smelled stale or iodiny. My companions had shrimp, about 12 medium large, with diablo sauce, around $11.00 I think, with accompaniments. Other friend had a combination platter (huge) with chile relleno, chicken enchalada and something else. Both friends very impressed by quality of all dishes (one friend is wife of a restauranteur). You Milwaukeeans are truly lucky/blessed to have such a fine & cheap place available to you every day. I really cannot recommend the seven seas soup enough.
I also tried to go to Taqueria Azteca on Howell, but I got lost once (at night) as Howell turns off unexpectedly and on another day, when I did find it, they were not opened until 11:30, and I was pressed for time--needed to check out. SIGH> Maybe next time.
I diverted, later, to Fortune Restaurant on 108th (traffic hell). Tried to get a vegetable dish, but place out of special vegetable (this, from Hong Kong menu); waitress suggested "seafood salt & pepper," and although I was already bursting with seafood experience (from Tres Hermanos), I rationalized that I would not have any good seafood available to me again for a long time--so I got it. Huge portion (again), light batter coated and fast-fried smelt, head-on shrimp, and squid, drizzled over with chopped raw hot green chili pepper, green onion, ginger, garlic, and sesame seed. (This was NOT stir-fry--raw choppings just thrown on top of freshly fried seafood.) Excellent, and took the left-overs home & not too bad reheated (but not the same, of course).
I also tried to find a hot-dog place near the airport where I had had the good luck, last time in town, to find a great Chicago-style hot-dog place. From memory, I think the place had mainly white interior decor with chrome accessories. But, place I stumbled onto this time--called "The Hangar"--was not the same. Low lighting and mainly wooden interior (as well as snotty, lackadaisical help, even by adolescent standards) were the rule. They had the ingredients to the expensive hot dogs pretty much down (although the dogs themselves were unnecessarily plump--not needed), but there was much lacking in the execution. Bottom half of one bun was hardened, probably from a day-long wait in the bog-end of a steam-table. Tomatoes were hard and under-ripe and so squirted all the other stuff out when bit upon. There was no salt or celery salt added to toppings. And the krinkle-kut fries were undistinguished, don't give a damn, fish 'em out of the freezer thingees. Tater-tots not much worse.
Anyway, thus ends my Milwaukee report and thanks again for the suggestions. Really made my trip.