I finally got around to installing GNU Emacs on my Nokia N900.
The instructions and package there worked for me. I did not find it necessary to do the maximization fix -- after turning off the tool bar, the minibuffer was visible for me.
Remapping the keyboard using the file provided does seem to cause some problems. The function key is no longer sticky, so I have to hold it down along with the letter key to get a number. That's not so possible when trying to type the number 1. Will have to look into that.
Now, to get Planner mode working well on it.
And yes, I will be trying out reading my mail using Gnus on it.