As pointed out: development takes time, and hardware has its limits. There is no one size fits all. Therefore, part of your choice is to pick a different device than N900 to suit your needs. Then you'd better get device with candybar design. Do you really need touchscreen? From this post I'd say a device like Nokia E71 is good for your specific use case as outlined here. You can use it easily with one hand. Now, does that make Nokia E71 a killer product and Nokia N900 crap? Ofcourse not. Every device has its pros and cons.