peppy is currently focused on developing the new lazer client, and as such, doesn't have much time to stock and manage the store. The tablets and keyboards are planned to make a return in the future, but no date is set. If you want a tablet sometime soon, your best chances are to just buy from somewhere else.
If you are patient, or just really want the osu! version and can be arsed to wait a year maybe (at the most probably) follow peppy on Twitter and keep an eye out for restock information.
Sorry for the inconvenience