Winelib is used to port Windows C++ projects to Linux, and Wine is intended to run full Windows applications. This project is intended to allow native Linux code to load simple Windows DLLs.
The closest analogy would be ndiswrapper but for userspace.'
Yes, I've written a windows dll loader for linux based on wine myself. It's fairly simple to add support for LoadLibrary() and GetProcAddress() to a linux program using wine libraries.