I think that the industry term for what you are looking for is a configurator. Usually a configurator has lots of logic behind it. For example, there might be drop down boxes for size and material, but if size ordered exceeds some limit, material choices are limited to aluminum or steel. Configurators can get complicated, but they enforce correct product specifications. Dell's configuator, for example, won't let you buy Small Business Server and Exchange because Exchange is included in Small Business Server. MISys had a configurator but I think they discontinued the product. Check with them at http://www.misysinc.com