The landscaper I planned to use stopped by with his business card with a dollar amount on the back (about $2k more than the bid from the company doing my room and about $500 less than the other concrete guy.) and said that he'd be leaving for a vacation tomorrow morning and would be able to start work at the end of the month. His bid is more thorough, includes wiring the shed, a PVC pipe to "lead" water to the street, both rebar and pig wire(?) and his concrete will be six inches deep. He's planning to shift the soil that he has to displace for the job around the yard to make the yard more level, too.
I think I have my guy. He wants half up front, but I think he's worth it.