Where to put standard functions that reference lib/mod methods

Wait.. How would this help though? I appreciate your input, but how does this help?

Well, it would avoid duplicating the same code in multiple controllers and/or models.
Narf's suggestion for using static methods is a good alternative also.
But if your main goal is to make your function calls shorter (and perhaps easier to read), then a seperate helper would be the best solution (IMHO). That's the way CI itself is solving this.