Dynamically choosing the main function

Hi, GHC allows choosing a main function at link time using the "-main-is" option. I was wondering if there is a possibility to choose the main function at runtime. Or even better, if something equivalent to "ghc -e" is somehow possible in a linked binary executable. If not, are there any plans to achieve something like that in future? Are there any theoretical, practical obstacles to that? Thanks, Harendra