Question : Is there a shared hosting running memcached ?
22 June 2012 : Hostgator Level 5 VPS or higher supports memcache, contact them for more information.
memcached (pronunciation: mem-cache-dee.) is a general-purpose distributed memory caching system that was originally developed by Danga Interactive for LiveJournal, but is now used by many other sites. It is often used to speed up dynamic database-driven websites by caching data and objects in memory to reduce the number of times the database must be read.
Memcached lacks authentication and security features, meaning it should only be used on servers with a firewall set up appropriately. By default, memcached uses the port 11211.
see more at http://en.wikipedia.org/wiki/Memcached
Now back to the question, Is there a shared hosting offer memcached pre-installed ?
There could be shared hosts offering memcached but it doesn’t make sense. If your application utilize memcache, that would probably means that your website is large and create many dynamic pages on the fly, so websites like this usually will not host on shared hosting. And secondly, memcached lacks of authentication which mean other user on the shared hosting is able to retrieve information from memcached if keys is correct.
You should look for a VPS or dedictaed if you want to utilize memcache – and honestly, that is where it makes more sense. If you legitimately need memcache, then typically you are out of the realm of shared hosting. Typical file caching methods are more then adequate for shared hosting.