Milk Paints

     I was at Lee Valley Tools Ltd. recently and was reminded of the Milk Paints they have available.  It's a traditional styled, acrylic paint for indoor and outdoor use.  
     The product is made by General Finishes, East Troy, WI, USA  http://generalfinishes.com/ and can be purchased here in Canada from Lee Valley Tools Ltd. at their store locations or mail order.

Image and info below cf. 

http://www.leevalley.com/en/wood/page.aspx?p=70940&cat=1,190,42942

General® Milk Paint      While not actually derived from milk proteins, this paint has hues akin to those of traditional milk paints. It dries to a satin finish, and has a more homogeneous, opaque quality that would ordinarily require several coats as well as considerable rubbing-out to achieve.      Formulated to a thick, creamy consistency, the ready-to-use acrylic-based paint requires no mixing, is easy to apply with a brush, pad or spray gun, and cleans up with soap and water. Can be applied over most water-based or oil-based stains, and top-coated with General High-Performance polyurethane, pre-catalyzed lacquer or conversion varnish.      Suitable for interior and exterior applications, it is UV-resistant and dries in 2 to 4 hours under ideal conditions. Available in one-quart (946ml / 32 fl oz) containers; coverage is approximately 100 sq.ft. Made in USA.      There are other suppliers of milk paints - here's a another such link,  http://www.homesteadhouse.ca/