P67 LGA 1155's are back: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007627%20600093976&IsNodeId=1&name=LGA%201155
I don't have the experience to answer #1 or #2 with anything other than hearsay/speculation.
#1-Yep, but it's overkill. You may as well ebay it.
#2-I think so, but the GTX560's only like a 25% upgrade and the GTX 460 is still overkill for PhysX. You may as well ebay it and get a GTX 260. I'd still go with a Radeon card. I saw 5870's for $205 last week on Newegg. That $50 can go towards a new build down the line?
But getting Sandy Bridge is probably best if you can afford it.