This thread prompted me to get in touch with GoLite customer service regarding the re-release of the Ion. The rep did say that they have a pack in the works that uses a lot of the Ion's characteristics, but sized for day hikes. He expects it to be released in 2013, probably in the spring.
He did mention that there has been a lot of interest from customers in re-releasing the Ion, but it sounds like there are no plans to bring it back as of now. This point was a little vague--probably intentionally--, but I don't think waiting on GoLite for a re-release is a workable strategy at this point.
Just thought I'd pass it on.