It doesn't exactly match your idea, however, there is a 'sort' option whereby you can sort what order the windows are displayed, including the particular channel names. Go to Windows > Sort in the menu bar.
You may also like to know you can press ALT+Left-Click on a Status bar window to collapse all of the channels of that particular server into its respective Status window tab.
I have to say I see little need for an increase in the number of lines the switchbar needs - there is a maximum possibility of 7 lines which is more than enough. I just can't fathom how anyone could seriously be chatting and need a lot of IRC networks to idle on, even if their friends have asked them to idle on their private networks....
Regards,
