today (22-JUl-2014) I spend some minutes to check the amount of patches available in mos for linux x64 by oracle version (only base releases and patchsets as 10.1.0.1.0 or 11.2.0.4.0 ). The following picture shows an example of the search filters used:
search filter examplehere is the result:
search results
10.1.0.3.0 is the oldest available release in the list.
Daniel Westermann's Blog 