5x100mm to 5x4.5" adapter?

The adapters are readily available in that configuration.
I have access to about 100 of them in various locations across the country.

Bear in mind, a 5 x 100 is not equal to a 5 x 4 small bolt pattern.
5 x 4 = 101.6

1.6 MM may not make a difference, as the adapter might still fit, but your lug nuts that holds the adapter to the drum/rotor is not going to completely sit flat in the tapered area of the spacer, since the holes in the spacer are for 100 MM spacing, and the small bolt pattern mopar are 101.6 apart.
Could be disasterous.

There are places out there that will make you a true 5 x 4 to 5 x 4.5 billet spacer.