At least one regional club (The Yorkshire Rat Club) has put on a special class for hairless in the past, Sarah. Dumbo rats caused a hell of a controversy when they first appeared on the scene too. LSCMRC used to have a special unstandardised class where dumbos could be shown as the NFRS had refused to allow them, sometimes they had a different judge from the main show though

Now there are some really good examples out there that are rightly winning top honours at shows.