questions/comments about latest e-commerce build for Drupal5.x

First, a thank you to the developers - the latest beta3 build seems to be very solid other than the shipping stuff
not seeming to work (which I presume you already know about and may have fixed already).

I've been exploring the possibility of building an e-commerce site for a customer using drupal, and it shows much
promise. One requirement they have is a taxonomy based search feature similar to what newegg.com has in their
"Advanced Search". I've been able to get it working using the taxonomy module and a slightly hacked version of
views, views_filterblock, and exposed filters, but I have one problem - namely that I end up with too many different
vocabularies for all the different types of products they sell which really clutters the top of the
node/add/product/tangible page.

Because vocabularies can be applied to specific content types, and Drupal 5 supports custom content types out of
the box, how hard would it be to make ecommerce, now or in the future, allow for custom content types? For example,
instead of having everything be just content type 'Product', how hard would it be to have content types 'Hard Drive', 'Network Switch', 'Processor' but still use the 'Product' plumbing? This would allow for common vocabularies like
'Price Range' and 'Manufacturer' to be reused, but the to be specific ones to only show up where they belong, thus
greatly simplifying product creation.