I'm thinking of getting a mac mini and moving my iTunes library to it and accessing the media via home sharing on my laptop. Is it possible to have my iPod/iPhone plugged into the laptop and sync it with the Mac Mini via home sharing?
No, don't think so. Just put a dock/cord near the Mini instead of attaching to the laptop whenever you need to sync.
Now, if you want to play music (you said accessing and syncing, 2 different things), home sharing allows you to do that on the laptop, from the Mini's iTunes database. I do that right now with 2 laptops and an Airport. Or, Airplay allows it to play on the latest iPod/Phones, I believe.