If you're looking for a DSI unit, I have a new Elite 5 DSI with internal GPS/Chartplotter for $350 OBO. I'll include the Lowrance scupper mount with it. Check this link out for screen shots.
http://www.thehulltruth.com/marine-e...pressions.html
The images of the carp are quite clear. This review is nice, because it does a side by side comparison of images from the DSI and the HDS units at the same location.
dsi%2010 by
lipripper1, on Flickr