As long as the query is using WP Show Posts, you should be able to use the AJAX pagination option. Is it not working for you? If not, can you link me to the page?
It’s sort of working, but it’s pulling in posts in addition to pages. Could it be a result of having two show posts areas on one page? Sorry, no link available right now, alas.
Also, any advice on how to set up a query based on a custom field?