Actually we have two lovely waterfront sims for rent/sale, both are Class 5 and they can be residential or commercial:
(1) Serpentia
http://slurl.com/secondlife/Serpentia/93/127/22
and,
(2) Knarley
http://slurl.com/secondlife/Knarley/127/164/
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.
We also have a 1/2 100% flat green sim:
http://slurl.com/secondlife/Olber/128/66/42
IM me or Scott Maroon if you have any questions