This would be totally cool. I probably spend half my time on physics stuff today - more effecient collision routines, etc. I agonize over whether to add physcis code here or there, whether the perf cost would be worth it. Wouldn't it be cool if ties were visable, were solid, could be shot, would hit a shape or prevent a multibot from going down a narrow passage, providing selection pressure towards smaller tie lengths.... All of these and each of these is new physics. It's all circle and rectangle and point and capsule intersection code, something I feel a lot more confident writing today then I did 6 months ago - something that would be quite ameanable to hardware acceleration I imagine - but its code I would love not to have to write....
One of the fundemental hurdles in ALife is that things don't interact unless programmed to interact. Things don't collide, bounce, drag, appear visible, exhert force, torque, etc. unless someone writes the code to allow those interactions. This is completly opposite of the way the physical world works. The physical world is messy. You have to go to tremendous lengths to prevent things from interacting in the physcial world and it's this messiness, this plethora of interactions that is critical and necessary or at least as necessary as other factors for biological evolution to occur.
So, the more interactions we can allow, the richer our virtual world will be and the more varied and complex the resulting organisms will be. I'm a total fan of this.