Yes, the date has been extended to June 1st, 2013.
Is there any way to purchase upgrades through the BFL website, or is there a different website for upgrades?
This. I'm looking to upgrade some units, but there doesn't seem to be an option for them anymore... Nice to know the deadline has been extended, but I want to get some orders in as soon as possible.
Go to purchase a BFL SC Single. On that page is a button to indicate that you're using a trade-in.
This is for buy one / trade in one, IIRC.
Might not be a convenient way to do multiples. I dunno. (Didn't need to know at the time.)