I recently picked up:

1. A cheap rear rack from Nashbar for $13. It has a dedicated bracket to hold my dynamo tailight.
2. 1992 Paramount PDG-70 Mountain bike
3.1989 Paramaount OS road bike (My non-commuter)
4. 1994 Trek 920 Singletrack Mountain bike
5. Xtracycle conversion kit

As I type it all out, I realize I may have a problem.....