I use both steel and forged aluminum 18" wheels. The steels were made a few years ago using implement outers (available from Miller Tire). The aluminum ones were from Wheel Vintiques and are currently available with most any offset and pattern. The narrowest was 7". They are a bunch of buck$$. My steels are 5.5".
I have heard from another person on the net that they are going to make some steel ones very soon. I would give them a call to get in line or find out the date. The more they hear from the faster they will do them.
Every steel wheel I have used needed straightened. None were or are perfectly straight. All the aluminum ones, cast or forged are perfect. Good Luck