I still haven't had any time to play around here. Plus all the designs here look so much better than what I could come up with. I had an idea to add though... What about somehow including a watermark or some way for the end user to also print the initial amount loaded on to the paper wallet? Of course people could add more later if they wanted, but at least they would know the minimum amount that should be held in the wallet.

Perhaps something similar to this design?

I was also thinking of something with kind of a trailing full amount like this:

10.12345678

Or doing the ¢BTC, mBTC, µBTC like this:

10.12345678

Maybe with the denomination just above the corresponding numbers?

I imagine most will want to just put a round number on their notes, but who knows? It might be nice to have something like this and I think it helps with readability.