Hi Antonio,
I've long envisioned a reimplementation of Fudgets using Monadic Stream Functions [1].
MSFs are like Yampa's SFs but with constrained side effects and without the mandatory continuous time (but you can put it back).
I don't think there is a fundamental limitation other than finding the time to do it. Sometimes there's issues with implementing arr in these kinds of systems (because it lifts a pure function and so it creates a widget with uninitialized state), but it can be worked out.
Ping me up if you want to talk about this. I was going to do something along these lines by the end of my PhD, so I thought a bit about how to do it. I also did some experiments for application debugging that used similar ideas.
All the best,
Ivan