I agree, I would just get a 28" barrel in shadowgrass. You already have the best semi-auto shotgun made today. Now if you want to add another gun in the arsenal that's a different story. In your price range there are some real good guns. Here is a list of some good ones to look at.

Beratta "Pintail/ES100"
Beretta "390/3901"
Franchi "612"
Stoeger "2000"
Weatherby "SAS"

You may even beable to find a Winchester SX2 for around $700.00