Finicky Financial Trading System
While this is listed under "investment analysis", it's really not meant for personal financial management.
It's geared toward trading floors - for example, the front office of an equity derivative shop.
As such, there really isn't much need to integrate with personal financial packages like GnuCash.
It would be nice to integrate this with QuantLib, though, which is very much along the same lines. I've been thinking about this for a while, but unfortunately it's not trivial. :)