FIrst off, better version of Xkbd. http://talk.maemo.org/showpost.php?p=408688&postcount=1 The delay between the keys being repeated by accident is much better in this one.
This could be done using Xbindkeys and XTE on an N810.
If you're making your own buttons, here's a great site if you would like to visually make them more appealing on the screen. http://cooltext.com/Ghost-Button