Hi Wolfen2, perhaps I can give you some insight on my experience with this and you can decide if its worth trying out. I too wanted to try some serious hybrid action, my favorite playthroughs through Baldur's Gate 2 were with a solo fighter/thief/mage.
As has been already discussed, its not really viable to spread yourself so thin in this one - but I believe I have managed to cover a lot of areas with my two lone wolf battle mages. I am not here to argue with the naysayers, I am purely sharing my experience. I have created a separate guide / topic to hopefully answer your questions. Please see :
my post
