Magento – Possible to use Multi-Select Attribute on Configurable Product

So, I may have hit a Magento limitation with this issue. We are working to customize a shopping experience for automotive products. We have only simple products loaded currently. Several of them all have the same name and only vary by the vehicle they fit. The issue with this is if you load up a category page, you see hundreds of products with the same name. In reality, those are a single "product" and the vehicle fitment data is what determines the final SKU.

We have implemented several different Year/Make/Model extensions, each excelling over the other in some way, finally settling on Amasty's Product Parts Finder extension. Currently, we are filtering the simple products based on the customers selection of year/make/model. If we can get the customer to first select their vehicle before shopping, this works sufficiently. However, if they do not select a YMM, they are presented with a terrible shopping experience.

Forcing the customer to select a YMM is not the solution I'm after here. I would like to somehow be able to assign a single SKU to multiple vehicles, as it is in the real world. When the customer lands on the product page, I would like them to be presented with Year, Make, and Model attribute value dropdowns. Selecting those values would dictate the single, selected SKU.

The problem comes in when we try to assign multiple vehicles to a single SKU. Currently, our "vehicle" attribute is a dropdown, so it will work with configurable products. However, it really needs to be a multi-select so I can assign multiple vehicles to a single sku. Unfortunately, Magento doesn't allow multi-select attributes to be used for configurable products.

Any ideas?