One bit signature doesn't make sense, even for
very small elliptic curves, for example p=79, n=67, base=(1,18). Even in that case, it is marked as a 7-bit curve (which could provide something like 6-bit security in practice, because 79 or 67 are much closer to 64 than to 128).
If you want to have one-bit values inside a signature, then you expect to have every value equal to exactly zero, or exactly one. This is what a single bit can store, nothing else. Which means, that (r=0,s=0), (r=0,s=1), (r=1,s=0), and (r=1,s=1), are all possible signatures. What do you want to get here? Private keys are in range from 1 to n-1. If n=2 in some very weak curve, then you have a generator, and a point at infinity, and absolutely nothing else.
More than it can fit in your RAM.
Well, if we assume, that a single bit is not what is stored, but what is known, which would mean 255-bit signatures, then yes, it won't fit in RAM.