My experience has taught me that only exceptional indivduals, for example, those "free electrons" that you have written about, would be worthy of a remote gig.

We had three members of our team work remotely. When this started, two were about as good as any other member of the team, but in a short time, both managed to alienate themselves, despite all the sorts of tools that have already been mentioned. Why? One person could have been in the office every day, but managed to work out a deal with a former manager who later left and was able to somehow grandfather the agreement. This person developed brain rot, got stuck doing mundane work, and is now perceived by many as milking the system.

The other person, while talented, wasn't seen as particularly exceptional. This person moved to work two states away and the rest of the team occasionally complained in private about how (a) the rest of the team did not have the same buying power as he did -- so the result for everyone else was a lower standard of living, despite equal contributions to the product, and (b) how they had to make special accomodations for him [extra setup for teleconferencing, netmeetings, and sometimes postponing certain types of meetings until he was able to fly into town...]. The question "why can't we hire someone else locally?" were brought up by several members during one-on-ones.

The third was a free electron. He was the principal of the original codebase, held several patents, is ridiculously productive, and well-liked among all the developers. He was diligent about accomodating remote issues moreso than anyone else, being available by IM, email, and phone during business hours, and his in-depth knowledge about the product made him invaluable to the team's productivity. Even if it took him several hours to get back with an answer to a question, it would have still taken the team days to find the solutions on their own.

So, yes remote workers can be a part of the team, but it's trickier than you think. The team's perception of the matter is vital, and they may not be easy to reveal how they really think about the situation.