Hi gate_pourri,
You mention a few neighborhoods, including Bucktown, but considering that most of our city's nice hotels are located in the Loop, Mag Mile, River North, you should probably eliminate Bucktown as a dinner destination, since I can't think of any nice hotels that are located within a few blocks of Bucktown.
There's an sushi thread right now
http://www.lthforum.com/bb/viewtopic.php?t=7831 that mentions a few places which would meet your specs. (Naniwa and Sushisamba Rio on Wells are not too far from any number of hotels. CoCoRo isn't mentioned, but it's also Japanese and on Wells. All three are terrific. Naniwa is more traditional sushi. Sushisamba is more trendy. Cocoro is traditional, but with less emphasis on sushi.)
Although it's a hotel restaurant, I've actually had some good meals at Aria in the Fairmont.
http://www.ariachicago.com/ Interestingly, they describe their menu as American with a twist, but I'd describe it as pan-Asian.
I've never been to Shanghai Terrace at the Penninsula, but have heard great things about it.
Hope this helps!