I bought one of these esata adapters a while back
http://i.imgur.com/RN3nu.jpg
but instead of the standard connections, it simply has one end as esata and the other end the normal sata used for internal drives. and it uses a normal sata power cable so you can take a regular hard drive without an enclosure and just connect it to the PC.
I have it installed on my work system and at home, so I can take video footage, then put it on my 90GB SSD and edit directly on the drive and get the full sata 6gbit speeds with sequential reads of nearly 500MB/s
For other devices that I have tried that actually use USB 3, (a few new DSLR's and external drives) the speed never comes close to even 200MB/s so a faster controller wont really help much with those devices)
I feel that esata has some serious potential if they could improve the connector or at least use the same design as USB but change the shape of the plastic thing in the connector to keep actual USB devices from connecting to it.