It's not a crazy thing to want, my data plan only ipod touch. I'd love an iphone if I had the choice of a data plan only. Course AT&T's data only plans (not that there is one for the iphone, except a TAP plan for the deaf, but you have to prove you are deaf, is still $45/mo @ 2gigs) are still a little pricey if you ask me.
It's not that I like my current cell phone plan, it's that I don't want a cell phone. Crazy, I know. And I'm a youngish whipper-snapper, not grumpy grampa. But I still don't like being reached when-ever where-ever. I like my privacy. And just turning the phone off is no good, people know you have it, and get angry when you don't pick it up.
But for communications I would be up for email or text messgs.
Now with the Sprint Peel you could get a cheaper data plan (about $40) and with the Clear iSpot 4g/3g wifi hotspot you can get unlimited data plan on a month to month basis for $25. (This is how I think AT&T and Apple will loose money.)
Ok, I can see where you're coming from. It would be kinda neat, but it's not going to happen. I think the market for it is just too small.