I have the same issue bro. If you're built like me (or me like you, whatever) then I certainly feel your pain. I'm a 48 jacket and a 33 waist. And I don't skip leg day. I can't buy anything from a Men's Warehouse etc. By the time they get the pants (which are usually 4" away from the jacket) to fit, they're Frankenstein and the pockets are all jacked etc.
If you know all your measurements, then there's a sick site to get shirts www.blanklabel.com
Also I found that the Van Heusen fitted shirts work well. They have regular, slim and fitted with fitted being the most slim in the waist. If you're like an 18" neck they should fit your neck/back/arms but be slim enough in the waist to not look like you've cinched a draw string sack around your waist.
For suits, Hardwick Clothing (which is 100% USA made) sells some good suits as separates which work well. You can order them in a 48 chest but slim waist and then order pants in whatever waist and rise (zipper length is rise). I hate how some pants have a long rise and it looks like you're wearing old man pants that should be pulled up. I usually get their short rise and do have one medium rise pair. Their suits are pretty affordable too, 100% wool is like $350 or so. You might be able to find a local tailor that can order them and then finish them for you (pant cuff etc.) If you can't find a local guy, several online suit places sell them.
Other than that, there are tons of custom suit guys. The Thomas James guy is always in my firm, but a decent suit from them is $1000. They want like $180 for a shirt. I think the blank labels are better and normally about $80. If you want to get a good suit, they make some good stuff. Their $699 suit is worse in fabric (wool/poly blend) than the Hardwick suit for $350. Plus they're sewn in like Brazil or something.
The top of the line, other than some full bespoke shop, is Hickey Freeman. The Thomas James guy reps them as well. A good suit from them is about $2500.
You want a super 120's suit (defines the pick count for the fabric) to get that really nice wool feel. The brand of suit doesn't really matter if the fabric is the same.
One thing for everyone to keep in mind is men's sizing. Most men that are a 46" jacket are also a 42" or so waist. Most guys get a belly, so jackets are fit more to accommodate a growing belly more than broader shoulders and a wide back. Also, if you've got big shoulders/traps it'll make sleeves short. A sleeve is measured from the middle of your back to your shoulder, then down your arm, so canon ball shoulders and good traps eat up inches quick.