Overclockers are "selling" MSI NF4 Ultras as being in stock at the end of November and the SLIs as early December. Priced £129.19 and £152.69 inc VAT respectively.
http://www.overclockers.co.uk/acatalog/MSI2.html
ASUS and Gigabyte boards too.
Anandtech has a short preview of the board.