I know they're big/were big in certain areas. That they're not the best use of space. And the roofing is a major concern.
Also zoning/permitting and such can be a pain. (I'm looking for a parcel that's still zoned agricultural in Florida.)
We'll see, but in the meantime, I'll start scanning that book. Just something to think about.
If I find a cheap piece of land and actually do it, I can sleep in my TD while working on it!