Q and Answer
Sam writes:
I’m tall. 6’3” or so. I like the look of a thicker knot in a necktie for some occasions, but if I try anything other than a four-in-hand I end up with a tie that is too short.   I realize there are longer ties available, but that brings with it the limited options and history of bad fashion at big-and-tall shops. Any advice? 
Sam, I myself am 6’3”, and don’t worry: there is help!
First of all: there’s nothing wrong with the four-in-hand.  Best tie knot around.  Versatile, rakish, handsome, never ostentatious.  However, if you want to fill out a spread collar, a bigger knot is great to have in your repotoire.
I agree with you that avoiding big-and-tall shops is a great idea.  Especially if you’re just tall - they tend to make clothes for people who are both.
Two sources for longer neckties come to mind.  On the budget side, Land’s End is a great source.  They offer many traditional necktie styles, and while their quality isn’t world-class, it’s very good for the price.  Here’s a classic Churchill dot tie, for example - long size is only $19.99.  You can also try some focused Ebay searching for long ties that may net some similar options.
If you’re willing to spend a bit more, you can get your ties made to your exact preferences by Sam Hober.  They charge $80 for hand-made neckties in any length and width, so you can buy a tie that fits you perfectly.  I bought the tie I wore in my wedding from Sam Hober, and while it took quite some time to arrive (the cost of bespoke), the quality is quite nice, and it’s a relief to have a tie with a rear blade that actually reaches past the keeper loop. Of course, Hober is also a great option for shorter men who have the opposite problem.
Hopefully some combination of these two will help keep you from looking like Oliver Hardy whenever you’re suited up.

Q and Answer

Sam writes:

I’m tall. 6’3” or so. I like the look of a thicker knot in a necktie for some occasions, but if I try anything other than a four-in-hand I end up with a tie that is too short.   I realize there are longer ties available, but that brings with it the limited options and history of bad fashion at big-and-tall shops. Any advice?

Sam, I myself am 6’3”, and don’t worry: there is help!

First of all: there’s nothing wrong with the four-in-hand.  Best tie knot around.  Versatile, rakish, handsome, never ostentatious.  However, if you want to fill out a spread collar, a bigger knot is great to have in your repotoire.

I agree with you that avoiding big-and-tall shops is a great idea.  Especially if you’re just tall - they tend to make clothes for people who are both.

Two sources for longer neckties come to mind.  On the budget side, Land’s End is a great source.  They offer many traditional necktie styles, and while their quality isn’t world-class, it’s very good for the price.  Here’s a classic Churchill dot tie, for example - long size is only $19.99.  You can also try some focused Ebay searching for long ties that may net some similar options.

If you’re willing to spend a bit more, you can get your ties made to your exact preferences by Sam Hober.  They charge $80 for hand-made neckties in any length and width, so you can buy a tie that fits you perfectly.  I bought the tie I wore in my wedding from Sam Hober, and while it took quite some time to arrive (the cost of bespoke), the quality is quite nice, and it’s a relief to have a tie with a rear blade that actually reaches past the keeper loop. Of course, Hober is also a great option for shorter men who have the opposite problem.

Hopefully some combination of these two will help keep you from looking like Oliver Hardy whenever you’re suited up.