I'm not sure about which Top Stats page are you writing about. Is it about the resetting the number of Top Stats displayed after you choose to "View more" from the home page, when you go back to that page again? Or is it about number of Top Stats resetting to 8 on the home page when you get back from the "View more" page, when you have chosen a different number there?

The "Top Stats" at the home page has only a global setting for all users for the number of visible results. The standalone "Top Stats" page doesn't save or read any cookies, which could be used to restore the number of visible stats to the previous state, either.

It can be done on the server side, but it requires modification of code of product displaying those stats which is not ours, which can be updated by its author, and then, after updating it to new version, there could be some conflicts even preventing this bulletin board modification to work.

As a quick solution, either of these pages can be changed by user scripts (scripts installed on the user side in Internet browser), and even save the last selected stats type and not only a number (works in Chrome/Chromium, Firefox [Greasemonkey/Scriptish extensions], Opera, and in Internet Explorer 8 [IE7Pro extension] but with graphical glitches, and only in Safari [NinjaKit] it doesn't save cookies when default security options are set).

An example of modified Top Stats by a user script for the Top Stats displayed on the home page:

I'm not quite sure what I meant, to be honest!
But the "let's just rewrite vBulletin" problem sounds good enough for me.

Thanks for the reply!