I work for the company that delevoped the SA-45, which is a 45-item derivative of the SCL-90. I don't think the OQ-45 is a derivative of the SCL-90. The only other questionnaire that is a subset of the SCL-90 (actually, the SCL-90-R) that I am aware of is the BSI, but it has 53 questions. It is distributed by NCS in Minnesota, and is not in the public domain. I'm fairly certain the SA-45 is in the public domain, but as you stated, the norms are not.
If you want more information, feel free to email me directly at sbk@stradv.com . If I can't answer your questions, I'll forward them to someone who can.
Sara Kind