My physics books all say that the two were indistinguishable, and gave the elevator example. It always bugged my profs to no end when I pointed out that they are always distinguishable. Frowns, bad grades, "troublemaker," always followed.
I'm so scarred!!!! LOL!
Yes, of course a "uniform gravitaional field" would be equivelent. But there ain't no such thing, unless someone can give me an example (then I'll go back to the class and shut up). Never has been, never will be.
The elevator thing taught to all budding physicists should have a disclaimer:
Caution: What you are about to hear is false, even reduced to a simplification."
Or am I wrong?
If you simplify your version of the example and assume that it's just you in the elevator (no pendulums, no instruments, just you, personally, as the solitary observer), can you tell the difference?
Is something wrong with the large, massive sheet?
And don't forget, for almost any conceivable gravitational field and any given level of sensitivity, there is a calculable scale below which the field is indistinguishable from a uniform field. That means that this problem is not irrelevant to the laboratory.
Or am I wrong?
You're missing the point. You might as relevantly have pointed out that the situation where someone is on a rocketship without knowing it is unlikely ever to arise. The equivalence principle is a far-from-obvious statement about the physical nature of gravity and inertia, not merely a practical limitation on figuring out whether you're travelling on a rocketship. Instead of pettifogging about the practical details of a given example, why don't you try to focus on the principle that the example was meant to illustrate?