For a cheaper 4-port SATA II PCI-e 4x solution than the ones listed, I'm successfully using a Rosewill RC-218 card. It uses the Marvell 88SX7042 chipset. The only note is that you need to make sure the jumpers are set properly. By default, two eSATA ports and two internal SATA ports are enabled. You need to switch jumpers to enable all four internal SATA ports (and disable the two eSATA ports).
http://www.newegg.com/Product/Product.aspx?Item=N82E16816132018