Hey Eliana. I would suggest checking out our tea room directory- teamap.com (link on top of the page) and looking through the tearooms, many of which have pictures. You'll find a lot of chintz and lace, but there are several more modern styles of tea rooms.
Also, the latest Bon Appetit magazine has a list of 'Hip Tearooms'. On the list: Tavalon (our own ex-Adagio's place in NYC), T-Bar in Philly, Samovar lounge in San Francisco, Beehive in Salt Lake City, and I *believe* two more, but I could be mistaken- I don't have the magazine here with me. I would look these all up online to see if they have any good images to get a feel on 'hip' tea rooms.
I have come to notice people go to tea rooms for more of an experience, than stopping in to grab a cup of tea- such as one would do with coffee. The tea rooms I've gone to require more of time commitment, more so than an in-out experience, but you might want to change this with your tea room, since it is for a younger crowd. But then it might not be considered a tea room (in many tea lovers eyes), but more so a cafe.
Lots of younger people are getting more into tea, so it's definitely a demographic that can be addressed. I would suggest offering multimedia in your place/plan- such as wireless internet, music, books, magazines, etc. Also look to offer a large range of teas- if your plan goes into much detail. Many younger people are becoming tea purists, but jazzed-up/novelty tea drinks (liquor spiked too) are becoming popular as well.
hope this info helps!