Dear X-Team, I still live vith a quite expensive Sun Type 6 USB Keyboard (US-Layout) having many dead keys. According to my Internet investigation keycodes are hardwirded at compiletime of the X-Server and unfortunately there is no official Support for such keyboard Layouts in version 4.2.x except for some obscure patch. but I have read about a promise it will be integrated in the 4.3 version. Are you aware of such an implementation so it is worth waiting for your release or give it a try and compile the original sources myself ?
-- Cheers Thomas