Lips just made one recent appearance so far. That doesn't mean he'll be used in the background a lot soon, but I hope it does. Hopefully he'll be used whenever the rest of the whole Electric Mayhem is used, or whenever a trumpet player is needed.
And I hope Roger Langridge finds a way to incorporate him into the comic soon. He claims that Lips' absense is due to not knowing what to do with him as opposed to not considering him a member of the band, but I've seen all sorts of opportunities for him to have been used.