I've seen SharePlus out there, but I don't think it allows for editing of documents and creating documents seems more difficult than it should be. Has anyone found a simple complete solution for doing this?
Yes, but you need a 3rd party app.
I have never used this nor do I work for the company: http://www.moprise.com/
I heard about it at a SharePoint Saturday event that I attended recently. The person who told me about it had very nice things to say. But I cannot vouch for it myself.
Since Office for iPad has come out this answer has changed: