Just another vote for the Apricorn enclosure with separately installed hard drive. That's my choice for customer backup solutions too. However, I've been buying the enclosures directly from Apricorn rather than Newegg. No MIR's to deal with and the shipping is resonable. Most hard drives from Newegg have Free Shippiing so that doesn't affect the overall price. $39 directly from Apricorn with no rebates.
http://www.apricorn.com/product_deta...e=family&id=56