+1 vote for Android tablets, especially the fantastic Transformer Prime with keyboard dock.
That said, your biggest problem with the iPad will be the on-screen keyboard taking up so much of the screen. It’s going to take some clever positioning to make what’s left of the screen useful. Perhaps a custom keyboard? Translucent?
Sorry, but a custom keyboard is definitely not on the cards. It’s technically possible but given the spectrum of keyboards that exist for different regions and the logic behind them it would be a significant undertaking to replicate the functionality.
But…
The app will only bring up the onscreen keyboard when you’re writing and editing therefore it won’t be ‘in the way’ all the time.
I don’t believe a translucent keyboard will work, either you won’t be able to see what’s under it or you won’t be able to see the keys clearly. I think apple’s split and moveable keyboard variants are a better solution and have the added benefit of being built in.
If you use an external keyboard then the onscreen won’t get in the way because it won’t appear. I’m typing this using the onscreen keyboard but if I was working for a long time on my iPad I’d be tempted to pull out my foldable Sierra keyboard… or maybe just use my laptop if I had it with me (very unlikely these days as it tends to remain deck bound).
Big +1 for Android tablets. Especially the transformer (with keyboard dock) has a large potential to replace my Windows laptop. I just need one or two more programs, Scrivener being the most important one of them.
Even Bigger +1 
Me using my Samsung Galaxy Tab with 7’’ and 1024x600 res would love to have some sort of Scrivener Lite. Coupled with DropBox this would really be a very nice thing.
With a Bluetooth-Keyboard even writing is no big problem. The res is the same as on my netbook, lol…