We currently have no plans to pursue this, so I'm closing the issue. Feel free to reopen it when you want to work on this.

Quoting Malte in a discussion on issue414:

"We might want to change to a nicer, less fragile interface for specifying portfolios in the future that exploits the fact 
that portfolios are Python code. Rather than having the portfolio runner in charge of adapting the arguments, the 
portfolios themselves could be in charge and do the adaptation themselves. [...] I think it would make the code much 
cleaner (there would be no assumptions on what the option strings look like) and also more general."