The perfect Asterisk Appliance

I have one customer that requires small asterisk boxes to use as appliance…

Althought I am aware of the new Digium Appliance that will come out this month (see here -> … s-de-1000/ ) , I would not need the analogic ports (for example) and I may need and rdsi line… My question is… Any suggestion to make my own asterisk appliance on a small box, with no hard drive, and being able to use “external components” for the interfaces ?

The simplest way would be a mini-ITX motherboard with a CF card instead of a HD.