Out of curiosity - were the files you needed from clients PDFs that required signatures? That seems to be the primary use case. There are some interesting startups around this area, but I haven't seen someone nail it 100% yet.
I've been thinking through the signed documents problem, but I'm not sure the market is ready yet. We've had legislation in the U.S. that legitimizing electronic signature for about a decade, but there's a comfort to a signed physical copy that is hard for people to give up for big contracts. I'm wondering what user affordance will finally break through that mental barrier, but I haven't come up with anything yet.