I work alongside many modpack creators, and many of them have been requesting to have specific mods to be ported to newer versions. Of course price per mod ported would vary based on difficulty, or per-hour work could be accepted as well. With that said, I am looking to commission someone to work with long-term to port specific mods that are requested.
If you are experienced in Java/Mod-development, please send me a PM with a summary of yourself, experience, and links to past projects. I will keep tabs on this thread for any general questions/replies.