Elecom's TK-U09FG keyboards have gears mounted under each key, depressing evenly even if just hit on a corner. Apparently, the cause of typos is hitting a key on a corner and having the keystroke not regstr. By detecting and activating the keys on the corners, this keyboard supposedly cuts down on typos. We don't know if this is true, but the keyboard is only 5040 yen ($42), so it may be worth a try.
Press Release (Japanese) [Elecom via Tech Japan]