HP Smart Array P212 ZM is known to work flawlessly in the Microserver and it connects directly to the standard SFF-8087 cable coming from the HDD backplane (re-routing of the hdd sas cable is required to reach the connector on the controller  )
- Rosewill RC-211 Silicon Image 2 port SATA II PCI Express Host Controller Card RAID 0/1/0+1/5 JBOD
- Supermicro AOC-USASLP-H8iR (as described in comments - works brilliantly. Also discovered you can put default LSI firmware on it and use the standard LSI Storage Manager software as well. V.happy)
- HighPoint RocketRAID 2720SGL
- HP 410. Can be found on ebay. Works with SFF-8087 cable. As mentioned in comments an updated firmware will add support for 3TB drives.