Wii Fit in stock checker - £69.99
Keep checking this link... I think PowerPlay Direct just had some in, but gone already... this is how I got mine a few months back though. Keep checking
You can put you're email in aswel and they email you when in stock.
Good Luck
EDIT: Wii Fit with Wii balance board
View Wii Fit stock history for this merchant
Last seen in stock: 06/08/2008 16:07:15 
sorry, I will keep an eye out though.