'Miniature' and 'Rare' colors are marketing ploys for extra $$$ by bad breeders. Bigrod48, just because you were told your bulldog is 'miniature' by the breeder, does not make it so. By breeding a smaller than average Mother with a smaller than average Father *MIGHT* produce smaller than average offspring, there isnt anything 'Miniature about them. Take a look at a 'Standard Poodle', compare that to a 'Miniature Poodle' and I think you will understand the difference between 'Miniature' and 'Smaller than average'
A Bad Breeder would tell you they have a dog that climbs trees and purrs if they thought they could get more $$$$ out of an unsuspecting buyer.....
and yup you guessed it right ! you would probably be buying a cat!. (Oh but we ALL know the difference between a Dog and a Cat, in this case..... well they didnt know there wasn't such a thing as a Miniature Bulldog)
As my Granddaddy the Carnival Game Operator used to say 'There's one born every minute . . . . '
I don't think you can purposely breed mini bulldogs but I think (correct me of I'm wrong) bulldogs can sometime give birth to very small bully's. I know my jovi was in a litter of 12 (I know crazy!) and one of her sisters is very very very small and will probably be 25 lbs at most. But all the other ones will be normal size. Mine runs a little smaller (not much though)
We researched this BIG TIME while we were looking for our girl (years of looking)...."Miniature" Bulldogs are not a breed...Like "Teacup" yorkies....Which we have one of. There is no such thing. Some breeders try to breed the bulldog smaller and call it a mini but there is no such thing IAC the AKC, it's frowned upon.
I also read that "forcing" their size to be smaller increases the chances for health issues. It's just like any other breed. Tea cup chihuahuas, tiny schnauzers, tiny this, mini that, etc. It's just a smaller english bulldog, and the breeder's breeding program consists of smaller EB's. No biggie, but they won't be up to standard/conformation following AKC guidelines.