As mentioned by Vadim previously, there is a problem with moving CachingSource and related classes to the core because of a dependency on the cron block. There are other cache related components in scratchpad that may in the future want a different home. Instead of bloating the core even more, perhaps it is a good idea to gather advanced cache related components in a separate cache block. There already exists the eventcache block which could serve as a basis for the new block.
WDYAT? -- Unico
