Judaism really does place a rather large emphasis on clothing. Hassidim are the obvious examples, but the commandmant to wear Tzitzit is clothing related. And a Kippah can be seen as clothing, though the nitpickers among you may claim it as an accessory. There are also a bunch of customs about Jewish women and their clothing, and anyone who spent as many years in yeshiva as I did can tell you that there are few things that people there worry about more than clothing.
Ethnic clothing is nothing new, especially for Jews. I remember some ten years ago there was some fashion designer who modeled his 1992 line of clothing after traditional hassidic garb. I can't remember the designer, but it was rather short-lived.
There are also a few places where you can buy clothing that have cutsy Jewish stuff on them, like chaiwear.com.
But now there is something that looks like it might have a bit more shelf lifeand a bit more stlye. First is jew.lo,a Brooklynite (a landsman!) no less, promoting these nifty Ts, and some philosophy or other. I think that everyone who can fit in to one of these ought to be wearing one.
We also have something a bit more deemure, but infused with an equal amount of pride at jewishjeans. Again, there is some philosophy or other attached to their clothing, but if you are like me and can't handle all that deep stuff, just wear the shirt. It's good for you.