If you have a look at ProjectorMultiply.shader and ProjectorLight.shader in the Effects standard asset bundle, they seem quite simple. I can't code shaders (because of SF ;) ), but to someone with your experience, it shouldn't be that hard to port them to SF. I really need that right now!

It's extremely minor of course, but I feel like relays have two uses:

• Bridging far out nodes, in which case the source node may not be in screen view
• Splitting vectors in named counterparts to be able to better identify them

In both cases, seeing the name of the relay is important. That's why I think the little "Relay" label should be editable.

Of course, I can easily workaround it with comments, but it's a little less elegant: