I've been thinking about a non-combat character, but since it's not possible to play the game without killing anything and support spells in Skyrim are limited to healing and Courage, i don't think that it would be much fun in the long run.
I was afraid of that too, which is why I didn't do it for so long. But I have been enjoying it quite a bit. She is around 35th level and has done the Mage's guild and is trying to develope her dragonborn abilities under the tutelage of the greybeards. Since I have done the MQ so much I rp'd that she distrusts the blades and Delphine so she left her after getting the horn of JW. She will soon realize that she needs to go back to Delphine though.
She is not a pacifist so I don't know if I would call her a non combat charcter. She just lets Jordis do the hacking for her, They can't stand evil doers and bandits so she is pretty combative. She has quite a few kills in her stats because sometimes Jordis' go on hers. She also will take a hack or two at something, especially when she is filling soul gems, she polishes them off after Jordis beats them down that way I can devote Jordis enchanted weapon solely to damage. She also uses her shield to bash stuff to help Jordis out, and keeps her heal spell in her right hand. She paralyzes, calms, etc stuff too while Jordis is fighting. Oh, and when stuff goes to a knee Jordis will quit attacking them so I will often finish them before they get up and smack Jordis in the back. She really quite adores Jordis.
Instead of making her a pacifist and doing the no kill thing, essentially I just use RP that she is not physically strong and becomes vilently ill when channeling Destruction magic. That way I can play her as I am. I have also limited her smithing under the assumption that her lack of strength makes it impossible to progess any further. It is 40 something now and will only go up if I find more equipment to fortify for Jordis.
I am thinking that eventually she might start meleeing after she has perked out all her best mage perks. Right now though I like playing her like this, as I have a bunch of melee magic characters already.