We have a few people in retail who came over from AHA. Mostly they come to retail because they tire of working from home (miss the social contact) or they tire of tier 1 iOS. Good luck switching to CPU. Have you considered being an Apple Certified Support Professional?
One of the downsides to working from home is that you never get that feeling of being a part of something. The 10' commute to work is nice but I had a lot more fun when I worked with a team that was able to sit together and bounce ideas around.
I'm not sure how exactly to go about switching to CPU. The internal job site only shows AHA and not specific queues. Also, my manager started about the same time I did and hasn't been around long enough to have a handle on how things work internally.
I thought about getting an Apple cert. but if I was going to focus on getting any certs they would be ones that actually had value, e.g. Cisco. An Apple cert. and $3.00 would get you a cup of coffee at Starbucks. They have no value whatsoever unless you work in an Apple store or on one of the campuses.
The other thing I noticed is that you can only go so far as an AHA. Tier 2, trainer, manager... that's it. If you really want to advance beyond being a phone jockey you have to be within commuting distance to one of their campuses.