FWIW, I've often heard what sounds like a little extra vowel between two of the same consonant. I put it down to the fact that -- as I've been told -- in Czech every letter is pronounced. Whereas, for example, in English, double consonants are usually just run together and pronounced as one.
Without some additional context, it is not standard. The "do" forms are usually there for emphasis or contrast.
-- "I don't have bread, but I DO have meat."
-- "He doesn't work on Saturdays, but he DOES work on Sundays."
-- "My sister has a motorbike, but she DOESN'T have a bicycle."