Wait, you have 75 tabs open? Doesn't the time it takes to locate the tab you are looking for exceed the time it would take to launch a new tab, and load the desired page?
The firefox awesome bar has an awesome (haha) feature for that: if you type an address, it will detect wether you have matching tabs open and give you the option to switch instead. It works over multiple tab groups and windows. So: locating a tab is quicker and it keeps the state of the page.
I presume that most people who have lots of tabs open, like I do, use addons that make finding tabs fast. I use Tab Kit to organize the tabs in trees, and Pentadactyl to give me fast search that is activated by pressing b. I can't imagine using a browser which doesn't have either or both of these features.