(I'm 6'5", 39"ish chest, 36" or so arms, 16.5-17" neck)
TM Lewin Roma fit are the only off-the shelf shirts I've found that fit fairly well (16.5×36" in my case). It's their slimmest fit and looks just about normal on me.
Wouldn't exactly say they're expensive – the last ones I bought were £20 each and they're better quality than the tailored ones I've had from Raja.
Other than the Romas (which were previously Roveretos) nothing at all I've found on the high street fits. (A couple of Zaras if I'm honest, but nothing recently and it's always a jumble sale – Lewin's fit is pretty reliable.) M&S shirts are a joke, you might as well buy a six-man tent from Blacks. It's telling that if you look at them on the mannequins in the shops they're all gathered and pinned at the back because they're made for people built like Bernard Manning.