But what do you want to connect to the MBP?
eSATA, audio, more Firewire, more USB, USB 3.0, ....?
For instance, I got a Sitecom eSATA adapter for 15 € and two eSATA / USB 2.0 docks for 20 € each for my 2009 17" MBP, and the 2009 MBP was prone to not having luck with expensive eSATA adapters, so I just gave it a shot and downloaded Mac OS X drivers from SiS (or so). Despite some initial kernel panics (my MBP has them a lot now), it works just fine, and with the correct HDD, I get speeds of up to 115 MB/s.