Horizons is starting to have a nice range of double beta ETFs for Canadian investors on the TSX. Looks like they just added two pairs of ETFs (up/down) for Natural Gas and Oil. http://www.hbpetfs.com/
I agree. If you are looking for ETFs for this and that, look up iShares, Proshares, Powershares, and Rydex. Yahoo has an ETF screener. Some like the QQQQ and SPY are most often on the most active for the NASDQ and AMEX. But the Yahoo list, has some of the ones listed are more thinly traded and you may not get the fills you want - especially I think if you do options. I don't know though, I am just guessing, because I don't trade thinly traded ETFs.
No - if you want to short oil, you should short oil. If you can't short the CL contract, then short the USO. The USO tracks crude oil pretty well.