Looking for a snap-apart connector & cable kit

I am looking for a product that may or may not exist.

What I want is a set of connectors that fit standard microprocessor boards
header pins, and let me create cables as needed for various uses. The jumper
wires shown here let me connect boards together, but I have to do it one
wire at a time: http://www.basicx.com/Products/Jumpers/bx_jumpers.jpg

But what I want is a plastic female connector (or kit) than can be cut or
broken apart and wires or ribbon cable added in fairly quickly to create my
own custom cables. For example, the connector part may have 2x8 rows of
female sockets, and I could snap it in half to make 2 2x4 connectors, then
insert/solder some ribbon cable into it. Then I could make cables to connect
to a Basic Atom, BS2, etc., and the other end could connect to whatever
components I need.

Does such a product exist ? What would be great would be a kit that comes
complete with a collection of connectors that fit header sizes such as .100
& .050 pitch pins, etc.

My apologies if the description I am giving is vague. If I knew better how
to describe this, I am sure I could probably Google on it and find it ASAP.