Budda: If you want a drop without the forward part you have two options (assuming you don't find the perfect mount somewhere):
1. Take a regular dovetail bar (no drop) (sometimes Smart Parts has the plain bar, no dovetail, but it's already properly tapped...you can also get plain aluminum bar stock and have a machine shop drill and tap for cheap), and drill and tap the far end to take the standard dovetail mount screws (10/32?)...this means that the holes have threads in them so it holds the screws from the next piece. The near end should have pass-through holes already drilled so that you can mount it to your gun frame. You then take a second dovetail bar and mount it facing backwards to the first one, using the screw holes that you tapped. This assumes that you can premount the air system and access all the holes. It can be done 'cause I've done it before, several times.
2. Custom make a drop down, and slightly back, so that you can mount a regular dovetail bar to it. I've also done this before so it does work. Usually you make the open part of the manufactured piece facing forward and the bottom part doesn't extend as far forward as the part attached to the grip frame...unless you flip the dovetail bar around so that it faces backward so you can access the locking setscrew...or unless you have the newer dovetail bars that have the setscrews mounted to the side of the bar.
2.A: If you know someone who can do some machining, just have them custom make you a whole drop down mount, complete with dovetail grooves. Just give them a regular dovetail as a guide...honestly, it might even be cheaper than buying one. I think just the bars are $40.00 in some stores.
Ray