This is already solved by Ctrl+F1 then, or the tab cycling experiment in opera:flags which enables tab switching in recently used order.
With those 2 together, it kind of works as expected. But, that only works if you hold down ctrl and hit f1 multiple times. If you hit ctrl + f1 and release and then hit ctrl + f1 again and release etc., it'll just cycle between two tabs.
But, even if that all works perfectly (as in, as how Opera 12 does it with left-clicking on a tab), it's not "solved" if it doesn't work with left-click on a tab. Thanks for the tip though.