This sounded familiar, so I poked around and found this:

  https://emacs.stackexchange.com/questions/33976/how-do-you-reload-a-dynamic-module

which suggests a workaround similar to what I vaguely remembered (fake it with numbered "module names" during development), with a little bit of automation glue. It's not something that would work as a supported user-level feature, but could be helpful for rapid iteration cycles.

Hope that helps, 
~Chad