I've heard everything from 6 months to 24 months gross income as far as the sale price is concerned. Ramster's post covers everything I'd be able to tell you
Other than that, I like pc's idea of "rinse & repeat"
As for my site(s), I doubt I'd get what I'd need to live off of if I sold them now, but in 6 months, based on what happens with my back, I might be able to sell it for less & still make out.