Thought I would post an update, in case any others are looking for 4-bolt wheels.
After much internet searching and discussing with others, I ended up buying a set of new rear 4-bolt wheels from Custom Metal Spinning (CMS)...the fellow's name is Walt Jenkins and he was very good to deal with. He will make any offset and width and has years of experience with the 4-bolt (and wide-5) VW patterns. I chose 6" width, with 3.5" backspace and these wheels weigh 4 kg each (just under 9 lb).
I had to use some cone watercooled bolts and cut them down to fit my stock drums.
For the front, I found a pair of good used Bogart 3.5" width wheels on the internet, complete with step-bolts. These weigh 3.6 kg (8 lb) each.
Also, picked up a couple pair of centre caps and Wolfsburg repro stickers. I haven't been to the drag strip yet, due to all the rain, but hope to make it out next Friday.
Here's a few photographs: