A bit ... Unnecessary, wouldnt you say? How can you 'cheat' in a single-player game?
I'm afraid I can't offer anything on-topic though. I haven't even bought the game yet!
you do know that cheating is doing anything outside the intended rules right? just that in a single player game, you're just cheating yourself out of the challenge intended by the creaters.
anyways, for spells not to fail, the in-game way is using spellmaker for less demanding spells. however, i think there's a mod that has 100% spell cast success, and just changes skill level to decrease magicka consumed per cast, but don't remember the name off-hand.