[martinaglv]

This looks very good! I took the decision of fixing everything to a grid early on and still pay the price for it (I have yet to make connections overlap properly). Having everything floating free on the stage is probably a better approach.

[chimi]

http://jsplumb.org/jquery/demo.html is a library to make all the connecting easier. I've used it. It's pretty nice.

[rplnt]

I like the fixed grid. It forces the user to not have a mess out of it. As for the connections, maybe the "metro map" style would work (with rounded corners).