I have a Malibu Pro 2 Tandem that I use both alone or with one of my boys (I have 4 under 11). Rigging a tandem is a challenge, especially if you plan to use it in a solo configuration as well, but it's possible and not a terrible experience. The biggest shortcoming is lacking a spot for a livewell, but I have rigged a bait tube in case I want to catch a few macks. I also rigged a fish finder that can be used in the solo or tandem layout. I'm not overly thrilled with the build quality of the Malibu though and will probably buy a Jackson Big Tuna for my next tandem kayak.
My father-in-law has a Hobie Oasis and it's lightning fast in comparison; A truly great boat, but not a good solo kayak. I had seriously considered the Hobie Odyssey, which can accommodate a Hobie Livewell and a solo configuration.
Sometimes if it's just me and my 4-year-old anchoring up in the bay and soaking baits near the eel grass I'll face his seat toward me, which works pretty well. It wouldn't work for a bigger kid though.
