Went for a really cheap "cherry 8000" keyboard which looks identical on ebay. I hope the keys are the same and wont be inferior in some kind of way...
All ISO G80-1800s basically use keys of the same size, only the front row may differ:Show Image(http://geekhack.org/attachment.php?attachmentid=14107&stc=1&d=1292581330)
ANSI (US) layout 'boards are a little bit different, though.
If you just want to change the alphanumeric keys, any Cherry MX compatible key should fit.