We do something similar to render large tables, but we use divs to layout our data. We establish the height of the scrollable area with a large div, and then absolutely position the rows within it. We have just enough real physical rows to fill the screen, plus a buffer of a few rows. The virtual rows are assigned to physical rows via modular arithmetic, so only a couple of rows change their data on scroll. (And are repositioned accordingly.)

This technique (particularly calculating the positions of the rows) requires fixed height rows. (There is a solution for variable height rows, but it's a bit more complicated.)

I originally got the idea by looking at google books years ago.

Here is a quick and dirty example as a self-contained HTML file:

  https://gist.github.com/3086578

(It constructs a list of 10,000 objects with title/description fields, and then displays that data in a table.)