Creatively, I think the design style is pretty cool. But yeah, the all over print trend is fading fast. Another thing to consider is production cost. This type of printing is labor intensive, so you will pay premium prices to get it done. And that will drive up your retail price. So it's not just the all over style that is fading, people just aren't willing to pay $30-50 for a t-shirt anymore. Especially now that all over prints are available at WalMart, Target, Kohls, etc, at reasonable prices.
Your best bet is to try to find a blank supplier that offers "washed" blanks. Try Alternative Apparel, Relik Apparel or Kavio. Then you can do a 1 or 2 color waterbase/discharge screen print. That should give you the look you're going for.
Another option would be to buy solid blanks from American Apparel, Royal Apparel, JS Apparel, etc, and have them custom washed. Then you can do the 1 or 2 color waterbase/discharge screen print.
It's also possible to use a solid blank and just use more waterbase/discharge ink colors to create the washed look and design. But you will probably get inconsistent results around the seams of the shirt when printing on a finished garment. To get the proper result, you would want to print on the fabric first and then have it sewn into a t-shirt.
Hope this helps and good luck!