limewireuserabuser is totally correct... filtering file size is easy math scripting, just "if, "then" and "else" - seeing as all incoming hits are put through your custom filter anyway it should be easy.

If it's something you feel will greatly aid limewire users you can submit it to the limewire production team - but I can't remember the email for it or the link to it, see the website http://www.limewire.com clicky

Seith