This playstyle sounds like a lot of fun. I can imagine shield stunning someone and then letting them have it with a fire spell. I tried a complete sneak no combat character once, just snook past everyone. It was very difficult at first, but when I got my sneak skill up, it was a lot of fun.
I tried that a while ago. I used a High Elf in Thalmor Robes and carved Nordic Gauntlets/Boots. With the Targe of the blooded shield and Lightning spells only Looked badass. He had a back story that as a Shield sergeant in the Thalmor army's branch of the Shield Brethren a feared black ops type organization known for being the first wave of attack. With Shield charge to knock down all that stand before him then spraying the ground with Lightning wall. Any who survived would be cut down with his razor sharp Carved Nordic sword or Bashed to death with his shield depending on how he felt.Was a totally enjoyable playthrough. No sneak just charge everything down even frost trolls could not stand up to this Power house
I don't remember the whole build and for whatever reason I didn't keep playing the character, but Fire Magic is so fun. I loved making people run around saying, "ah, I'm on fire, I'm on fire!" I keep meaning to mage some sort of fire mage but never seem to get back to it. Maybe I'll try it today.
I've never played a battlemage using a shield... Actually, I've only ever even played one Battlemage. Two-handed casting is just kind of a necessity for most spells in Skyrim to be effective; it goes double for Destruction, because Impact is the only thing that makes that school an efficient use of Magicka.
Probably the most surprisingly fun play style I've found is the Summerset Shadows approach that I started somewhat recently. Basically, focused on sneakery and using staffs for summons so you can flank people with sneak attacks. Flanking strategies are actually a LOT of fun, because it's really hard to get the timing right and not be seen in the chaos.