There are few niches in which a hibrid build that is good at both spellcasting and fighting in melee.
I have been experimenting with a couple of custom dwarves over 2 playthroughs and discovered that Str/Int hibrids that use sword and board in conjunction with necromancy and warfare can become very tanky due to the fact that intelect buffs the amount of magical armor they get as well as the damage from certain necromancer spells such as mosquito swarm.
One of my best main characters was a thieving battlemage lizzard with bull rush, mosquito swarm and chameleon cloak as my starting skills; 11 in wits,10 in the rest,12 in str and int. I was able to steal very early most of skill tomes I needed with relative ease and the free point in persuasion helped me dodge jail on several ocasions (it was hilarious,really)
