A request for a bit of odd advice

But I guess that's why it's here, in the fringe.

I'm a writer in Manhattan, and my day job requires a lengthy bus commute. I want to utilize that time to write, and so I am here to ask for advice on a gadget to accomplish said task.

Some caveats:

One, the bus ride is bumpy, so writing by hand is somewhat out. I can decipher what I've scribbled, but not always and it is very difficult.

Two, the bus is rather crowded, so I can't bust out an actual laptop to type.

Three, I'm a writer, so not much in the way of funds.

I have an iPad, and an iPhone, but I think I'd like something with an actual keyboard. I've been thinking about something like an OQO, or even an older phone like a Palm Treo or an HP Ipaq. Any thoughts, comments or ideas would be very welcome.