the IE side by side thing is a PIA.
I have asked for that several times but i do not think we will ever see it.
why: the IE "parts" are used by many other programs in the system. they would i think have to install 2 versions of ie and make one of them register with COM the "old way" and the other would have to register differently and then you would have apps that would show html the IE6 way and others the IE-9 way ..... IE and the dlls for it are hooked into a bunch of things .... messy and bad but it's been that way for aonmg time and would be huge work to fix. many apps would break if not patched / updated and many of them are not MS apps.