Shouldn't be a problem, as long as you adhere to the List and the itemtemplate mechanism it uses.
I show for each item an image with a couple of lines of text.

For a screenshot:

http://www.badaap.nl/wordpress/wp-co...let_series.jpg

The list on the right is the buffered list and loads 500 items per 'page'. So after scrolling down 500 items, 500 new items are loaded.

The list on the left too, but it loads all items at once. But it shows the index bar and grouping working with the buffered list.