A pretty far-fetched idea, but I thought I would bring it up in case anyone knows anything about this area:
If you've driven on I-5 just south of downtown Portland over the last couple of weeks, you may have noticed a major tree-trimming project on the west side of I-5 (between I-5 and SW Barbur), between the Corbett and Terwiliger exits. This is part of an upcoming construction project on I-5. While the area is relatively steep (in the east-west direction), as a result of the tree-cutting, you can now see a a relatively level dirt road (maintainance road) going parallel to I-5 (north-south) and the area looks like it would have room for a trail or two or three. Obviously not a huge area, but probably bigger than Gateway Green. Also, there are no Forest-park hippies walking their dogs here, and ODOT will have to do a lot of work (replanting) here anyway. A perfect opportunity to add a few new trails practically down-town, if you ask me. See http://www.oregon.gov/ODOT/HWY/REGION1/iowaviaduct/ Does anybody know anything about this area or whether this is something that would be worth pursuing?
As part of public process for developing trails, Oregon Parks & Recreation Department has opened up a survey to capture user feedback about the Stub Stewart Trails. This has specifically been opened up to get input about Stub Mountain Bike Area trails which have been constructed by volunteer labor over the past several years. At least 90 responses are needed to meet requirements for feedback about this new trail. 
