Abyssinian mice have rosettes similar to abyssinian cavies, and are often referred to in Europe as "rosette" rather than abyssinian. The gene is recessive and mice can exhibit anything from two rosettes on the hips to ten rosettes across the body (more may be possible with selective breeding).
Unfortunately due to the softness of a mouse's coat the rosettes don't seem to hold their shape very well. The abyssinian isn't a very popular variety for exhibition purposes in the UK, and any would-be abyssinian breeders might find it hard to get their hands on foundation stock. Any that can be found would at present require a lot of work to get them to a showable standard.