I actually had sushi last night at Red Hawk Casino for Thanksgiving. The only one I was able to eat was their cucumber and carrot rolls and veggie chow mein. Just make sure they don't use any dairy in them to make them stick (rolls). Ask questions if you can get a hold of a waiter. I was barely able to ask questions because it was hectic. Only thing I was able to ask was: do the steam buns have meat in them? and what about the potstickers? Both had pork :( love potstickers and steam buns. Anyway, I smuggled in some low sodium soy sauce too xD so there is a condiment idea.
Call ahead to make sure they can accommodate your diet.If you live close by stop in and pickup a menu.Make sure they don't add mayo.Careful with the tempura it can be high in fat.See if they can make you a low oil and salt veggie stirfry.
If so, insist they clean their utensils and cutting board, unless you like your roll to reek of fishies!
Maybe inquire what goes into their sushi rice. I worked a sushi restaurant that would add vinegar, sugar with a few added chemical ingredients in them...
Making sushi at home is fun and at least you know what is going in it!
Telling your server that you have a fish/shellfish and dairy allergy would automatically require them to use separate cutting board and knives, for liability purposes as well ... going off of Windlord's suggestion
I don't know how you could eat with the smell of fish around you and the very likely possibility of contamination of fish guts and bacteria, parasite eggs etc. I would only make my own at home if I were you. A good recipe here: Woman vs. Man Carb Eating Contest! Who Will WIN!?
Jon, meet pwnage! :)