Here is one that has an aluminum hub (machined from bar stock). This is what I'd purchase - the price is right and would make your project quite simple:
http://www.corvairunderground.com/govair/pulley.htm
Small pic:
CorvairHub.jpg
Not sure this guy is still in business . . . worth checking out. Obviously if you buy just the shaft and bearing, you can make your own hub. But, if I had his to start with - would save some time and the price he showed was more than fair.