The "hidden keys" or 3/4ths layout is a nice idea, but I don't think it would be practical for speed (which is my major issue). The "triangle-key" layout (above) is a shape I've never seen before, and it could really work nicely.

Customization is always nice, but I can see how implementations would be "very long and hard work to do." It's basically why the maemo OS updates updates take so "long." However, I think it would be worth it. Maybe it could be a paid download, that way it would be worth it to put in the programming time.

Generally speaking, the biggest problem is that apps in our community are not made with an eye towards profit (aside from the small market share). Not always a bad thing, since most are making programs for love of the device (and free too!), but we need more mainstream awareness if just to get people to spend time on programming and receive just rewards.