Do some serious looking at Green Man's site.
http://www.seedbankupdate.com/su.html
There's a LOT of good info regarding reliability.
There is one seed site with the initials PS that I would avoid. Very recently the owner has been doing some really unprofessional stuff.(I don't want to mention the full name to avoid giving him free advertising.)
I'd suggest you spend a few hours looking at seed selections.
My personal outdoor favorite is Durban Poison. Reliable, and they get very large.
Here's a pic of a four pounder from '09.
The second pic shows Durban Poison on the left and a large Kali Mist in the upper right.
The DP is shading nearly 50 square feet and is about eight feet tall, after a lot of Low Stress Training(LST).
I've had specimens that easily top ten feet.
The main stem was bent over and about twelve feet long.