I was also looking for eSata options on my MBP and I took a cheap gamble on an Express34 card from Bytecc and it is working really well. It only cost $37 from Newegg.com and has been working well ever since. I am pretty sure it is Sata 150 and not Sata 300 but at this point it matters little as the MBPs seem to be hindered in over throughput from Express34 anyway. Unfortuantely, Newegg seems to have deactivated it on their website so I am not sure where else you can get it but you may want to check with their site:
https://www.byteccusa.com/product/xP-card/bt-eces2.htm
For enclosures, I went with the macsales.com options. I ended up with the Mercury Elite Pro which holds two drives and it is also working really well. All in all, the setup was really cheap and works beyond the expectation considering the price.
-gl