Funny, I've been thinking about doing the same thing for a while. I used to have a Workbench disk we got from a guy who copied a lot of disks for us back in the 80s, called "Alan's Workbench". I remember it had heaps of useful utilities, a disk copier, and it was laid out differently to the standard 1.3 Workbench. I recently found the disk, but it's full of mould and wrecked my floppy drive when I tried to read it. Luckily I found a cleaning disk on eBay and fixed the drive, but the disk is rooted.
I'm working on a 4 colour icon set for Workbench 2/3, so I'll swap all the colours around and resave them for Workbenc 1 too. It won't be a full set, just the main ones and a few default icons.
I found this on Aminet, it looks like it's packed full of goodies to try
http://aminet.net/package/misc/antiq/OldHacksIt'll be good to have an enhanced 1.3/1.4 disk to run on the A500s here.