I use my Sealskin socks for fall kayaking. I also find them too bulky for cycling (except perhaps mtb'ing and my commuter shoes are big enough to fit them, I suppose).
I just did a google search on "Waterproof cycling booties" and came up with this:
http://www.mec.ca/Products/product_d...=1161733688554
..and..
http://www.bikemania.biz/Shoe_Covers_Booties_s/203.htm
Hope this helps.
I don't think my Adidas covers are waterproof....