Wetlook World Forum

You might try to find someone who does "preform" out-of-the-shelve T-shirts.  I've seen techniques used towards this in theater wardrobe through my years with Cirque du Soleil.  I don't know if they do this physically, chemically or otherwise.

If I was on my own with such a task, I'd try "differential shrinking through heat": select a larger shirt than needed, soak the lower and upper parts with water (leave the chest area dry), and put in the dryer full heat for a long time.  Presumably, the wet area will shrink more than the originally dry part.  (Or should it be the other way around?  Try it out and please keep this forum posted!)