I have been reading some posts on hedging/market neutral portfolios. I think the simplest feature to implement would be to allow 2 port variables: Hedge Index and Hedge Percent.

For example, use the RUT20000 index and cover 66% of the portfolio value.

This would be a very blunt analysis tool, but would let one see the effect of hedging with various indices, ETFs, etc... Now, I leave the fun part of finding the algorithm for margin/cash impact etc... up to you! Hint: don't bother with the margin/cash effect - keep it blunt for now....