Hi Adam,

please have a look at http://www.mediawiki.org/wiki/API:Recentchanges
This is a way to get the list in 5000 lines, but you may repeat it. There must be some final limit, i tried to repeat it manually, and got the first 20000 item.
I am just working on an API interface for special pages, I will try to give priority for this task within the project if it is not too urgent for you. Or you may create your own API query using this help page and query.py. Write a loop while the resulted dictionary has the key 'query-continue'. 5000 is the maximum to get in one query for a bot.