I bought mine from Leer and it fits great yea it has the wings at the front but you use what you got. It's a great place to set your beer when playing in the back.
To answer your question I don't know of any with the bead rails so narrow a regular cap wouldn't sit very well I guess you could make something to extend the width and set something on that.
There use to be a company that made one that stepped out at the rails but I searched everywhere and couldn't find any reference to who made it
2001 Edge Chrome Yellow ORP 3" body lift 4.0L 5 speed auto
Kenwood DDX6019 with NAV and Bluetooth
Two Kenwood KAC-7203 powering Four Polk Audio Momo MM571 5" X 7"
Kenwood KAC-8103D driving two Polk Audio Momo 10" MM1040 DVC
200 amp alternator and a Boss Audio 3.5 farad cap to keep things bumping.
1994 Mazda MX5 (Miata) Turbo 274 hp 232 ft lbs torque
2005 Honda R12X Aquatrax stock
2007 Honda TRX450R lots of mods