I'm not sure you're going to be able to find an external enclosure with multiple eSATA connections. The closest thing I can think of that you'll find would be getting something like a 5 in 3 drive cage, some SATA to eSATA cables and a molex to AC power adapter, plus a card that has multiple eSATA ports, and cards with more than two eSATA ports are pretty expensive. Even then it's a pretty ghetto setup.
In the end you're going to be better off just getting a case that better suits your needs. I don't know if you need rack mounted but this cheap $60 Norco 2U rack mounted case has mounts for four 3.5 inch drives plus a 5.25 inch bay you could fit another one in with brackets for a total of 5 drives. So unless your friend was going to sell you that Cineraid for ridiculously cheap, just upgrading to a better case will probably be cheaper.
http://www.newegg.com/Product/Product.aspx?Item=N82E16811219032