When I switched over to 5-on5.5 the stock axles and rotors I had at the time did not have enough "meat" to allow re-drill.
The AlloyUSA axles I bought came with a dual pattern, and would not fit inside the my old rotors.
After tons of searching and trips to local parts outlets, I bought '94 Ford F150 rotors. Unfortunately, they are not a perfect fit. The main issue is the pilot ID of the rotor is 3.870 inches, while the axle pilot OD is 2.824. To solve this, I had 2 "centering rings" machined to fit tightly over the axle pilot, and "just right" inside the rotor pilot.
The spacers were .250 thick x 3.865OD with a 2.824 ID.
They work great, and I've not experienced any vibration.
The second issue with these rotors, is the lug holes are .675inches ID, and the axle lugs are 1/2inch OD.
At first, I used bushings (.625 OD x .500 ID)but found the taper on the lug-nuts centered the rotor.
I needed rotors that were ~ 1.00inch thick to match my calipers. If your calipers can take a thicker rotor, you may be able to use front rotors off of a CJ. Otherwise, you may be able to buy custom rotors from a vendor like TSM; but when it comes time to replace them, they're "custom", and said vendor may not be in business anymore.