Hmm, it's a bit tough to come up with something that fits all these points, in particular my recommendation may not match if the "offer me the option" is meant to be somehow interactive:
Duplicate File Hard Linker
There's another catch as the name may give away already. This creates hard links. These only ever exist inside a single volume (in many cases equivalent to a partition). If you have a bunch of files that are spread across different volumes, you won't see an effect here.
However, the semantics of the symbolic links as introduced in Windows Vista aren't quite comparable to the symbolic links one may be used to from POSIX/SUS systems. So even if there was a tool like what you seem to be asking for, you'd probably need something along the lines of
stow to make it really useful.
You don't specify in your question, but if you are on certain Windows Server editions, you could be lucky to have some form of Single-Instance Storage (SIS), which - like symbolic links and junction points - are based on reparse points. Newer server editions seem to use a block-based form of deduplication.