Yeah, figured the 'catch-all' newbies thread wouldn't be the most appropriate place, but alas, this is my only option for posting. Thanks for the tip though.

They ended up making it into my account, and after talking with bitinstant they explained that there must have been some significant delays during the mixing process. So, all is well.

Some takeaways / tips for blockchain.info if they should happen to see this -

• Consider adding a sentence or two to explain what "private" means effectively (or at least a link), and timing expectations. The box is checked by default, so some explanation is necessary. Had I understood the process and timing implications I probably would have unchecked it. I definitely wouldn't have been as alarmed by the process.
• Update your guide for cash deposits to explain the private option. This is currently missing from your guide.

Thanks!

It's been 15 hours...

Clicked 'Cash Deposit' on main screen after logging in. Filled out form, went through zipzap, payed, got confirmation from zip zap.

0.96660915 BTC should have gone here: http://blockchain.info/address/1EPaF7RbigfkWbpAXGxkYyzMucnoanrxc5
instead they went here: https://blockchain.info/address/1HEJPsQ6g1sggHominxE3FWkyFxQKwztWb

Am I missing something or is there a problem?