Re the cirrus147.com site, how can they do what appears to be ad-hoc rental of an N-reg, without a Dry Lease?
I suppose one could download a lease document off the booking website, print it out, sign it, fax it to some number, all before the booked flight date. Maybe this is what they do but I didn't check.
I also couldn't see a minimum flying time requirement but I would never rent out such a plane unless the pilot was going to be doing say 30hrs/year; less than that and he will not be sufficiently current on the type, IMHO.