For mandolins, try one of the solid top Kentuckys, the s in the serial number means solid top (i.e. KM250S). If you get lucky, quite often the solid top Strad-o-lins can be very nice and can record great! I found a good Stradolin at Players Vintage Instruments a few years ago, they have them from time to time.
I would also check Ebay often for a Gibson Ajr or A0. They are built like the fancier Gibson As, but as they are less fancy, you'll often see these go for under 1000.00. These sound great if they get played a lot, don't sound good if they never get played.
My Gibson A2 sounds terrific with the back of a Royer R121.
As for Dean, I can only give you info about the mandolins. They are very inexpensive and are not worth that money. My bet is the banjo would be similar.