Example: purchasing configured products

[Bob Haugen <linkage@interaccess.com>]

The main difference in purchasing configured products is that
product ID or SKU is insufficient to distinguish what the purchaser
wants.  Other configuration properties must be added.

Configuration properties come in different flavors:

* Component selections, as in the computer business, where
  the purchaser selects a base computer model, and then selects
  from options for CPU, monitor, file storage, communication,
  operating system, and other components.
  A significant feature of component configurations is constraints
  among the components: for example, some components may
  require others, or the number of components may exceed the
  capacity of the selected base model, or some components
  may be incompatible with other selections.

* Cosmetic options like color, trim packages, etc.

* Dimension selections, like in the window business where
  the purchaser selects a base window model and then
  specifies length and width.

* Grade or potency, where the purchaser specifies 
   "Grade A" or "at least 70% concentration" of an
   active ingredient.

* Lists of measurable properties, like in the paper business 
  where purchasers select a base product type (e.g. Kraft paper)
  and then specify a list of properties like caliper, wet strength,
  etc., sometimes also specifying the tests that should be used
  to measure the properties.
  In some industries, this is called an Assay.

Any other examples of configured product purchasing?