It depends on what kind of pants you're looking for. For hunting/hiking pants....its hard enough to find 36". I think 38" would be like finding a unicorn.
Tall lengths in outdoor apparel generally aren't very tall IMO. You're best bet is to get the longest lengths you can find and take the hem out. Or, you may also be able to contact the company directly and get some extra material and sew it on the pant legs. I've heard of some companies sending out some extra fabric from returned items they can't sell.
Mostly hunting, rough Arizona terrain. Looked a pnuma brush, but only 36 before you wash them and they shrink. Did call a few , no go. Most of their sewing done overseas. No money in it for them. Like you said Unicorn.
You've got to be careful these days because you might find 38's and then get them and find that they have a very short rise (like 3" shorter) so they're still short........AND tight in the crotch. I've found a few of those the last 10 years. I have to call companies and verify just how long they are from the top of the waist to the bottom of the pant legs as well as their inseam. My favorite pants are the old Cabela's Microtex that came unhemmed at 37", and they're 49" from top to bottom. Sure wish they still made these and the Lite version as well. The Lite version comes in at 48".
I have a 38” inseam and kuiu 37” work well for me. Crye precision has pants that are long enough as welI . I also have pnuma for rain gear that is plenty long
Also check out the Fjallraven Barents Pro pants. They come un hemmed—I have a 35” inseam and they were dragging on the floor before the wife altered them
@mgmicky Yeah, the unhemmed Fjällräven inseam is 38.5", which is pretty fantastic in my opinion. They're the only pair of outdoorsy pants I've come across where I haven't wanted more length. Really tough and comfortable, too.