Recently I had a gentleman tell me that there were different sizes of Bichons. If this is true what is the size range, does any one know?

In the UK a Bichon should be betwen 9-11". In the US, I believe it's 9.5 -11.5"

If they are a 'differnet size' they are unlikely to be purebred or they may have health problems. People seem to be crossing Bichons with anything these days. They also seem to be a particular favourite of the puppy farmer who couldn't care less what size or shape they grow to be.