Oh, yes! I'm partial to Apple products, so AirPlay only support would be fine by me, but you'd be able to snag a wider market by including Bluetooth, so I think that's a must.
Stereo, for sure. Portability would be great, too. I once lugged my Audiobytes (sans sub) to a cabin in the woods and it wasn't very convenient so I haven't done it again. To make these Axiom AirPlay speakers portable, in addition to sizing them right, you should offer a briefcase-style carrying case as an optional accessory. You could make such a case double as an outboard rechargeable battery pack with flat lithium ion or even flatter lithium polymer batteries (as found in some laptops) along the bottom of the case.