I found a Sony 300 at bestbuy.com. I know this is one of the older models, but for a child's first reader I think it is fine. You would have to load it more often since it has smaller memory, but I am always adding to my Nook library anyway.
http://www.bestbuy.com/site/Sony+-+R...&skuId=9453799
I would grab them up fast if you are interested since who knows when they will be out.