Yes, and now I've already implemented the buttons. The arrows normally aren't shown. They would only show up if there's insane number of levels. Say, if you have more than 20 pages you'll see "1", "2", ..., "19" and right arrow. If you click the right arrow you'll select page 20 and will see left arrow, "20", "21", ... It wasn't an easy thing to do, not too hard either.. I still get surprised by how good MMF2 is at bugs. Here's a nice one: expression Buttons Count( "Page Marker" )*X Step( "Page Marker" )/2 is interpreted as Buttons Count( "Page Marker" )*(X Step( "Page Marker" )/2)
For filtering by date I'm planning to use the latest one among saves dates and world folder date. Have you looked for an MMF2 component that would allow getting files dates?