As someone in the same boat–6’2" 312 and shrinking (was up near 400 for awhile)–I suggest LL Bean, or llbean.com if need be.
I do have some LL Bean gear that I dig, but I’ve found that Cabelas carries a lot of good quality clothing in sizes that, well, fit, and their customer service is second to none. Now, if you want more than just ‘outdoor-ish’ clothing, go somewhere else, but everything I’ve purchased from them wears like iron, and if it doesn’t, they handle it. Can’t say enough about 'em. Plus, they have a HUGE selection of Under Armour clothing and gear, which has become my new obsession.
Even if you’re right square in the supposed middle of the bell curve, you might be screwed when it comes to finding clothes that fit. At 5’10" and about 175 lbs., with a 30 inch waist, you’d think I’d be able to just grab stuff off the rack.
Nuh-uh, doesn’t happen. I wear anywhere from a M to XL in shirts, depending on how a manufacturer decides to size things. I’ve got longer arms than normal proportions, which doesn’t help when it comes to long sleeved shirts. Men’s jeans are supposed to be sized by actual measurements. Yeah, right, in bizzaro world maybe. Some 32" inseams are way too short, some look more like 34s. Waist sizes are vanity sized now, since the tape measure says I’m a solid 30", but pants that size are almost big enough to fall off my ass, and thanks to squats I have the exact opposite of noassatall syndrome.
Which brings up another problem. Even if I could find a 28 or 29x32 — and the waist was by some miracle not an actual 28" or 29" measurement, which would be too tight — there’s no way I could fit my legs or butt them. I had that problem before I lost weight, when I was up to a waist size of around 33–34 and was soft and flabby elsewhere by my standards, but it’s worse now. I’m not all that huge and ripped from working out semi-regularly over the last couple of years, though I’m definitely showing some muscle.
Still, I’ll be damned if I can get my legs into most of the pants that are nominally my size. If I go up to a 32, the waist is baggy as hell, but at least I don’t feel like I’m going to split the back seam when I sit down. They must be cutting those things for guys with fat guts (who don’t want to admit that they have a paunch) who also do next to no walking, running, or any kind of manual labor.
You’d think from my location that I was bitching about Japanese sizing. Nope. On my last trip to the US, I tried to replace some of my badly worn-out jeans with new ones. Levis, Old Navy, whatever. I wasn’t picky as long as they had decent cloth and construction, and fit well. Couldn’t find anything that fit properly in three different stores, spending about 45 minutes at each trying stuff on. So, I gave up.
It’s worse here. They cut things for the metrosexual Japanese pretty boys who have ankles the size of my wrists and waists the circumference of my thigh. Pants are hopeless. I haven’t found any that fit in years. I had to order my last couple of pairs of semi-dress pants from overseas. Lands’ End is actually pretty decent, though the overseas shipping adds a bit of a premium. I wear a minimum of LL (a size rating equivalent to an XL in the US, but about the size of a normal-to-slim-US large) in shirts here unless I want it to be tight across the shoulders and chest. I don’t even bother trying to find long sleeves that fit anymore; I just roll them up. That’s something that can’t be helped since even in the US my ape-arms make it hard to find sleeved shirts that fit properly without being a bit too big elsewhere.
Sponge Bob Square Pants! 
I’m near-as-damn-it the same size as you (6’5" - 205) and used to find 36 length Levis all the time. These days they are rare but I find the 34 length fits just fine. When I was a scrawny teenager I wore 29x36. :eek:
Yeah, I’m in the same situation as you, I feel sorry for all the odd sized folks. 
I’m 5’ 10", 185, and wear 36x32 pants, medium or large for shirts. Shopping is pretty easy for me. 
Looking at it again, I’m amazed, lol. If you’re 240 and fit in the same pants I do, you must have limbs like tree trucks. Either that, or you are made of neutron star matter.
Oh hell yes - I never feel like such a freak as when I go clothes shopping, which I have to do tomorrow since I’m in the US on business and everything is half price with the exchange rate!
I’m 6’4", 230lbs, and have a 38" waist and a 34" inseam. I usually wear shirts in XL. Jacket size is 46L. Neck is 17 1/2". I don’t seem to look like a freak, in comparison to others, but I am a bit bigger than the average I’ll admit.
Buy Levis 501s pre-shrunk? Forget about it. Either >40-40 or <36-32; nothing in between. When I actually find some in my size, I buy like 12 pairs as I have no idea when I will see them again. Dress pants? Forget it. Only ‘relaxed’ fit is ever in my size and those look like a tent on me. Shirts? Dress shirts almost always have too short sleeves or too tight of a neck; polo shirts constrict my biceps; t-shirts either end up being made by Omar the Tent Maker or by providers to the boy band contingent.
Most stores in the UK don’t even stock any trousers or jeans in anything over 36 waist. I’ve been looking for a 46l overcoat for like 6 months; I figure since it’s late spring going into summer I might find one next week when I don’t need it anymore. Big and Tall are definitely for people who are both; there’s no one who really caters for just tall.
Best move I ever made was getting 3 suits and 6 shirts custom made in Thailand three years ago; I’m going back next year and plan on stocking up again. They are the only dress shirts and suits I have that actually fit me well.
I’m only 6’2", but I used to wear 28x38 Levis. It was a sad day when I first bought pants with the same waistband as inseam. (I’m 200 lbs now.)