I heard from a guy at Mazda (Mazdaspeed Motorsports actually) that they aren't planning an AWD MS3. Price would be higher, car would be heavier AND slower and they think they've hit a sweet spot of the market here. For $23K, nothing comes close so I'd have to agree.
If they could get more power to make it faster than the FWD MS3 even with the extra weight and AWD powertrain loss, then maybe they could do it but it'd still be $2K minimum more expensive. Today, closest thing is Volvo S40/V50 T5 AWD (same chassis as Mazda 3 with turbo 5cyl, 218hp, 236 ft-lbs, 6sp) but it's like $30K