I introduced a guy at work to hammocking. He's super interested, but he thinks his girl friend is not going to want to hang "alone" (on her own two trees).

I suggested sharing one tree at the head and using separate trees at the foot end. He's going to run that by her, but just incase she won't go for it, what do you think about this idea.

He wanted to know what I thought about a spreader bar to keep them from being crammed together, while still allowing them to hang from the same to strong trees.

There would be separate tree huggers and suspensions for each hammock. They would just be hanging from the same trees. The spreader bars in question would be at the head and foot of the hammock, and would keep them close but not constantly fighting over the center-line between the trees.

Here's a pic for the visual folks.