I only see two obvious solutions here.
We could take the total number of safecoins closer to the limit of what the network can handle... could it handle 10x and 45bn? Then we trade in 10:1 maids for safecoin. Not a very pretty solution really and what happens when even those hit $10 each in a few years?
Or, we find some way to award fractions of safecoins to farmers with whatever divisibility mechanism we use.
Really, the second solution is the only one that fits with a truly scalable network that is accessible to everyone. If it replaces the internet Safecoins would be worth thousands and you'd be lucky to win one or two a year, so no casual user will be able to get on board without being able to buy fractions of a safecoin on exchanges.
Given the investment potential for the network currency, there is a good chance it will surprise people with a very high value even before it is being used much.
I don't doubt this issue will get cracked, but it is a problem if we want to maintain a large, healthy decentralised network. Even at a few bucks this will be an issue, and we'll probably hit that before real SAFEcoin even exists.
As others have said though, David and the team have cracked way more complicated challenges than this already. This won't be a problem as long as we solve it properly. I'd really love to see a divisibility solution that allows farmers to be rewarded with fractions of a coin. And it needs to stay really simple and user-friendly of course. I like the idea of farming pools or something, as long as grandma doesn't have to have any idea that this is what is happening and it is all kept super obvious and simple for her.