Depending upon the dimensions of the closet, that might not work out so well... If it is the traditional closet depth that is basically just deep enough for a single clothes hangar, extending the back of it forward is going to make it to shallow to hold clothes... On the other hand, taking a few inches or a foot (depending upon the size of the door opening) off one of the ends might very well work for something like this. In a lot of houses there are various dead spaces in the framing where walls are placed around it, but there is no way to get to the space. It's often done with the air return from your central air-conditioning / heating unit. Most people won't notice that the sides of the closet don't go as far as they should with respect to where another wall probably goes from another room. I used to have a house where the entire area underneath the stairs was a dead space -- no doorway or anything in there. I ended up cutting a hole in the pantry closet in the master bathroom so that I could get into this area. I needed to get back there to run some satellite cable anyway since the entertainment center was against the stairway wall... It would have made a nice place to hide a gun safe...
