Souces of Timing/Drive Pulleys

I have been slowly gathering the parts for a retrofit of a small
knee mill. The table size and travel is about equivalent to a
mill/drill - 6" X 20" (size&travel).

I will be fitting it with ball screws. And I am looking for a
2 to 1 drive reduction.

Now to my question -

What have all you guys been using as a source for your
timing pulleys'?

I have searched on the web and not really found anything.
Unless I am looking for the wrong thing. MSC and McMaster
didn't really have anything applicable. I found 2 to 1
combinations on MSC in the XL belt style, but the largest
combination (30 to 60) only had a bore size of 5/16 & 3/8.
These are too small and would need to be bored out. I would
rather not do that. (assuming the hub has the meat to bore out)

Also, I have a limit of about 3" outside diameter for the small
pulley.

Any input or a point in the right direction would be great.

Mike

P.S. - What about prices? It looks like I can spend more on
2 sets of pulleys (4 total) than I spent on my motors (surplus)