Google App Engine has some information about Memcache limits:
- http://code.google.com/appengine/docs/quotas.html#Memcache
- http://code.google.com/appengine/docs/python/memcache/overview.html#Quotas_and_Limits
However, total allowed size of RAM/memory store for a single application is not specified. It's known that no objects above 1MB is allowed. Do you have information?