With regard to the thin stripe down the middle look, do bear in mind that very tall, very large men can often benefit from not merely longer than average neckties, but wider than average ties, as well. True, tie width should be influenced by other factors (like, lapel width), but a man who needs a 67" long necktie might be advised to wear something more like a 3 3/4" wide tie, than a 2 1/2" one.
Sadly, this means that most silk knit ties - even if acceptable for length - can be undesirably narrow for a very large man. Not that this problem is in any way limited to knits.
Definitely this. Check out Sam Hober. They custom make some fantastic ties, and will make them to any specifications--length, width, etc--that you may need.