Germany (almost entirely ISDN now) is the only place that I have heard of which has landlines that can receive SMS. It's unfortunate, there are many times when I've wanted the same thing, haven't ever found it. I believe the SMS routing in the US is extra convoluted, and less than reliable, compared to most countries which have been on GSM for years. Maybe someone familiar with how it's done can elaborate.
One thing I've wondered is how, since our mobile numbers can not be differentiated by prefix, they determine the number can receive the SMS. It may be a database lookup somewhere, but, then again maybe they just attempt to send it regardless of whether or not it is a mobile?