I think this would be a more than great option to save a lot of trouble. But also it is a teribly hard one as for everyone uses different schemes (if there is any system in it at all) for storing alternative versions.
Generally I use consistent filenames that apply to the DAM convention of never use the same filename in different occasions. But for me this is only true for my RAW originals. JPG versions of them keep the original filename and get JPG extention. I usually only store them in different folders but some people (some times even I) may rename it to call {fbas}_email or {fbas}_thumb.
But how would the PM catalog know from itself or by the user pointing out that an image is an alternative of another image? And how should it handle their relationship? And how many versions should be treated in how many ways? Different applications (image viewers), and even the OS may generate temporary files for images that should be handled as well. The user generates small res e-mail send versions, web previews, low res quick JPGs, mid and high res JPG versions for different uses, maybe TIFFs for printing. Just another version for one use, another for an exhibition and another for a portfolio. How to relate them to each other and how to discover, display, and manage their existing relationship.
I find it is a good but teribly hard question. I cannot tell what I would prefer to use to solve it but I am courious to find out.