The first thing to be said is that rules are there for the guidance of wise men and the obedience of fools - to some extent the same applies to SOPs and aircraft limitations. Most limitations which appear in the Flight Manual are 'set back' a little from what has been demonstrated during the test flying (cross wind limits for example) and most structural limits have fairly substantial margins. Thus, under extreme conditions, it is usually safe to exceed them. But NOT in normal operations and some - not at all. This is where you need to know your aircraft.
For example, at max altitude in coffin corner. In totally calm conditions it is possible to fly exactly at the point where the high speed buffet meets the low speed buffet (I have done it on a test flight). BUT you need to know the stall characteristics of your aircraft and its controllability at high Mach numbers. I would NEVER recommend doing this on the line.
However, if you have an emergency and it is necessary to land above the cross wind limit, it is possible provided you consider the effects of the failure that has caused the emergency and the effect it might have on the controllability of your aicraft. Equally, if it is absolutely necessary to land overweight and the only option is an autoland, then do it. This is what airmanship and command is all about. As a previous poster has written it is better to have a slightly bent aircraft than a hole in the ground.
My second point, any company that objects to pilots seeking more information about their aircraft, either from the manufacturer or the relevant CAA, needs its collective head examined. The need for accuracy and truth is paramount.