There was a similar thread thread to this a few weeks ago
http://www.thehomebrewforum.co.uk/showthread.php?p=548588#post548588
I have to say I am very particular about clean glasses like Covrich.
If you are really seeking a sustained head on your pint try Torrified Wheat. You will have to do a mini-mash with a diastase containing grain like Pale Malt since TW does not contain any. That's what commercial brewers sometimes use (Black Sheep Brewery mentioned TW as 10% of the grain bill when I did a visit last year) and I have tried it recently and it works.
I did read on here a while back that the longer you leave beer to condition the smaller the bubbles that form when you serve it and so the head will be stronger and last longer, but I have no way of knowing whether that's true or not.