External 2.5" SAS/SATA RAID with Firewire & USB

[virtual.rx]

I would need a min. of 4 2.5" drives and support for RAID 1 essentially.

So long I have found this:
http://www.cooldrives.com/qu2saiihadrm.html

But it is expensive.

And without external enclosure:
http://www.addonics.com/products/raid_system/ae4rcs25nsa.asp

Are there any good options out there?

This is needed for portability and reliability.

I have a Macbook, so no place for a RAID-card

 

[virtual.rx]

I think I'll get this one:
http://www.istarusa.com/storage/external_enclosure/mini_dual/vage220uf.aspx

It's about 170$.

Although it is for 3.5" hdds it is very small, and seems durable.

Any opinions?