I'm familiar with and have traded U.S.-listed LEAPS and I've always used the CBOE quotes page you linked to. So, I too was surprised I couldn't find 3M (MMM) LEAPS quotes at that page, even after checking the "List all options, LEAPS, Credit Options & Weeklys if avail." radio button. Used to work!
Fortunately, I was able to get access to the full chain of option quotes from the CBOE's other quotes page: Go to the "Quotes & Data" menu, then select Delayed Quotes - NEW! Here's how:
- Near top right of the main panel, spot the "Get Quote" label followed by the text input.
- Enter "MMM" in that text input, then click the Play/Go icon at right.
- Click "Options" in the top navigation of the resulting panel.
- Choose "Jan 2012" from the "Expiration" drop-down of the resulting panel.
- Click "View Chain".
I think the new interface is terrible: it's too many steps to get to the information desired. I preferred the all-in-one table of the Delayed Quotes Classic page, the one you linked to. As to why that classic page isn't yielding the full chain, I can only suggest it is a recently introduced bug (software defect). I certainly was able to get LEAPS quotes from that page before.
On Yahoo! Finance option quotes: I don't know why their chain is incomplete – I can't see the logic, for instance, as to why MMM Jan 2012 60 calls are missing. I thought at first it may be lack of volume or open interest, but nope. Anyway, I don't trust Yahoo! to provide accurate, reliable quotes anyway, having seen too many errors and missing data in particular in the feed of Canadian stocks, which I also trade.
I rely on the exchange's quotes, and my broker's real-time quotes. I check Yahoo! only for convenience sake, and when it actually matters I go to the other more reliable sources.
For what it's worth, though, you can also get full chain option quotes at NASDAQ. See here for the 3M (MMM) example then click on the "Jan 12" link near the top. However, I would consider CBOE's quotes more definitive, since they are the options exchange.