I saw this thread referenced by the OP in a request for new features and thought I would provide an answer.
You can generate a sequence number for your files in the Rename, Move, and Copy tool and it can be the exact number in the playlist.
Here's a File Name expression that will do pretty much what you are asking for:
CustomData(#)-[Artist]-[Name]
Fill that into the FileName field in the Rename, Move, and Copy tool. You will have to specify the directory you want in the Directories (Base Path) area. I couldn't find a way to automatically fill in the Playlist name either, so you'll have to type that manually in the Directories area. If you don't have too many playlists that shouldn't be too much effort.
Remember to use the Copy mode only! No move, no update, no rename. Also be sure to look at the preview pane on the right to see what directory and filename it is going to use when it does the Copy. Make sure it's the name you want and you should be good to go.
One more thing: This will produce numbers starting a 1 and using single digits until it gets to 10. If you want to zero pad everything, so that it starts at 001 (for example), you can do that too. Just modify it to look like this:
Padnumber(CustomData(#), 3)-[Artist]-[Name]
The 3 is the number of total digits. If you want more or less, change that number. Again, look at the preview pane to be sure you will get what you want.
Let me know if this works for you.
Brian.