There are already five pages of replies and OP replied twice (if am not mistaken) but we still don't know what he is looking for exactly and what's so special about a casino offering only slot games!
It's clear from the comments above that such casino does not exist or all members who have replied are not aware of their existence.
but some of the few i have seen have great features and loads of benefits most especially for players with high rank accounts. So am thinking if one can find new casinos that offer such services.
Can you name few of them and what benefits they do offer so we have a better idea on what you are looking for?