Actually I have Two Sims for rent/sale, both are Class 5 and they can be residential or commercial:
(1) A lovely beach/waterfront sim
http://slurl.com/secondlife/Serpentia/93/127/22
and,
(2) A very nice flat green sim
http://slurl.com/secondlife/Schock/127/132/44
They are both Full sims on Mature Mainland - no covenant, so you can do what you want.
If you rent then there is NO up front money - after all you are renting so why pay anything other than the weekly rent.
They are also for sale, however if you rent I will cancel the sale and not sell it as long as you are renting.
I also have a 1/2 flat green sim:
http://slurl.com/secondlife/Olber/128/66/42
IM me if you have any questions