Might be worth contacting Font Bureau to see if an italic is available. I was able to license the italics for Benton Sans before they were displayed on the FB web site.

Also, I can recommend Klavika from firsthand experience.

Stainless is one of those “square sans” faces that crop up in discussions often. I know that whenever they do, people always tout Klavika as their favorite.

EDIT: There are a bunch more in this thread. I did some searching for you, and all the types mentioned except for Cachet have italics.

EDIT 2: Oops, sent down to the bottom.

Sophisto is also an alternative, with a wide range of weights including dingbats and patterns as well. MAybe too characteristic?

http://www.macrhino.com
http://www.psyops.com/html/spec_sophisto_ss.html

Zemestro