small video in place of product image?

My personal opinion is that this isn't something that needs to be part of the basic cart as much as a design element that gets built on an as-needed basis. 

EI has a long list of requests for much more generalized features that would benefit the wider community, and adding the support for your particular site in order to achieve this would not be that great an effort.

If you have the resources to produce the product-specific videos needed for such an implementation, then the fees associated with adding a custom field (to the database + product admin) that would contain the Flash link and the design time for page layout should certainly be within your budget.  Adding such a field to the product admin is a few hours of coding, plus whatever design time goes into the revised page layout.