"A guarantee of bank secrecy was added to the Swiss Constitution in 2005 "
http://baumanblog.sovereignsociety.com/2008/07/does-ubs-have-t.html
Just read Baumans blog. It contains lots of good info.
This article deals mainly with the EU savings directive, but it should give you an idea of whats going on.
http://baumanblog.sovereignsociety.com/2008/07/eu-tax-directiv.html
The Swiss recently passed an amendment to their constitution guaranteeing bank secrecy. But of course that doesn't apply to the US subsidiary of a Swiss bank. If you want a secrecy you can't leave a paper-trail in your home country.
Paul Krugman writes a great deal about this topic in his blog. The post below is about metal futures, but it applies equally well to Oil.
commodities-and-speculation-metallic-evidence
To sum it up, unless you are buying up the actual stuff(Oil,Wheat, etc) it doesn't affect prices.
I think you got it right. Index funds etc. have to roll their positions every month, making them sellers as well as buyers of commodities.
Speculators are the usual scapegoats when something is wrong.
Apparently the International Energy Agency is also tying to talk up oil :D
http://bespokeinvest.typepad.com/bespoke/2008/05/iea-warns-of-po.html
"The world's premier energy monitor is preparing a sharp downward revision of its oil-supply forecast, a shift that reflects deepening pessimism...
People who say that speculators are driving up the price of oli are forgetting that you have to stockpile large amounts of crude to drive up the price. See Krugmans article for a nice counter-point.
http://krugman.blogs.nytimes.com/2008/05/13/more-on-oil-and-speculation