The one that clifftall points to is nice. But, it's not too hard to make one up if you are handy. Take a spare mini-fuse and short it out. Grind off the plastic above the ends of both terminals. Solder a pair of wires to the exposed terminals. Select a place for a toggle switch, solder the leads to the switch and install the switch. I put my switch to the right of the ignition switch on a flat part of the dash. Since you are replacing a fuse, you need to put an inline fuse somewhere in your wire run. I soldered in a Radio Shack fuse holder and a 2 amp fuse (same as #8).
My motto: Why buy it when you can make something ugly your own-self?
'09 Pleasure Way Lexor, Chevrolet Express 3500 chassis, 6.0L V8
Last RV, 2005 NRV Dolphin 5342 (2007-2014)