Anyone know of any mods out there that allow you to cast spells in your left hand with a two handed weapon equipped?

Because of the way Two-handed fighting is handled in the CK, I doubt this will be possible without a heavy script. It could be possible to make a script that assigns your two-handed weapon to a one-handed weapon while you use magic, but it would make two-handed weapons really OP..

There aren't any mods and it most likely will not be possible. If a two-handed weapon is changed to behave like a one-handed weapon by any means, it will use the perks and skill level of the one-handed skill. This is not the sort of thing that has been possible to change in any previous game.

Why would you have to change it? Couldn't there be a script tied to a casting button just like Oblivion that let you cast if you weren't swinging?

Not with the way the new Spellcasting works in Skyrim.

Casting button? There is no casting button.

Thanks for the replies. Guess I'll just continue to swap then between one and two handers when I need to drop a spell.