Can I get a daily list of stocks (and commodities?) that crossed the 50-day MA going up or down?

If you are a member, you can write a scan that will do that for you. You might want to limit the scan in some way - by market, like NYSE or NASD, or by market cap, like over 100M, or volume - over 50000 shares average, etc.

If you are not a member, check out the Free Charts tab. At the lower right is a box titled Additional Tools and Reports. Check out the Predefined Scan Results tab. I didn't see specifically what you are looking for, but you might find something else useful.