Here in Sweden it's impossible to get a Banshee caliper since it not sells here.I suggest to use a bike caliper with the piston out over the exhaust in around the 10:00 position on the rotor.
They have more clearance than most sled calipers I have seen in how they are made.
It looks like you need one from the right front from a banshee from the pics I have seen.
Once you have it mocked in place, you then fabricate a peice of steel that connects on its mounting area to the origional mount point for the cable brake.
Run line, bleed and hook up brake switch on bars.
I have done conversions on V-Max 4 and used SX-R or SRX brake parts and line and handlebar controls.
Trick is making a parking brake that works.
I have some calipers and controls from some SX and SRX.
You would have to make your own mount plate.
I might even have a few disks if you wanted to convert to a bigger disc.
Did this for TSS Vmax 92-96.
Same concept may work on other sleds.
https://totallyamaha.net/showthread.php/88900-Hyd-Brake-conversion-for-Vmax-500-600-Vmax-4
opsled