I don't think I ever had a A4 printer that could not also print Letter. It is almost certainly the exact same models that they also sell in the US, but with just some bit flipped in the firmware to change the default paper size.

My current printer, like most printers I believe, can be configured to print custom sizes. The maximum is something like 9 or 9.5 inches wide IIRC, and the length can be set much longer.