maybe get the rim and spokes cheaper online, and then have someone build it for you? You may be able to knock off some of the totally rebuild cost. I did that with one of my bikes and got the rim and spokes at about 25% of what I would have had to pay at my LBS. I like to support my local bike shop but in that case I needed my bike fixed and didn't have the kind of money it would have cost to get it done.

If you look around your area you may have a used/new bike shop, they are almost always a great way to pick up a cheap single wheel.