It is possible to configure multiple memcached servers when using IpcMemcachedProvider backend. The device data however might end up on different memcached servers because the hashing algorithm takes only the key into account.
PHP Memcached class provides *ByKey (addByKey, setByKey, getByKey etc) functions which accept $server_key parameter. The extension then will hash on the $server_key to select the memcached server. This would increase performance as there will be only one connection to one memcached server.
This is a rather big change as it requires interface update.