Burn, baby burn, 700 Megabytes!
Just found an interesting article on how to burn 700MB CDs with your Mac (scroll down).
Basically, you put the files in a folder, type hdiutil makehybrid -o myburn.iso path/to/folder/ into terminal and it'll create a disk image that you can then burn with Disk Utility.
Now, you may not know it, but Finder actually uses a disk image file at /System/Library/CoreServices/Finder.app/Contents/Resources/cdr80-proxy.dmg as a template for the disk image into which you drag your files in Finder. I tried for a while to coerce hdiutil to create a disk image with the same specs, but 700MB size, but sadly I didn't manage anything but an "Error 2" when I inserted my blank CD.
I found hdiutil imageinfo image.dmg which gave me the info on Finder's image, and I tried various calls to hdiutil create ... and hdiutil convert image.dmg -format UDCO -o cdr80-proxy.dmg without success. Any hdiutil wizards out there who know how to achieve this?