Is stretching hash several times basically the same as bcrypt? As I understand it, the main advantage of bcrypt is stretching so it becomes slower to crack overtime. But, is using a "good enough" algorithm (e.g., SHA-2 family) then stretching until it's slow enough for your liking is pretty much the same as bcrypt?

Note: I understand scrypt is superior but let's assume bcrypt is the best for now.
bcrypt operates using the Blowfish block cypher. It does not use any kind of message digest function (such as MD5, SHA1, SHA-256, etc.) internally.

Of course, I think what you really wanted to ask was, "would using a traditional message digest function with some amount of stretching give similar security to bcrypt?", and the answer to that question is probably "no". However, we can't answer that because we don't really know how you would accomplish the stretching. It's probably reasonable to say that stretching in some way would achieve similar security, but you would need to account for what bcrypt was designed to do.

bcrypt does have the advantage that it's "slower" than the message digest algorithms, but that's not it's main goal. bcrypt was designed not only to be slow, but to scale poorly on FPGA and GPU architectures. As you mentioned, modern FPGAs have gotten quite a bit better and serve as reasonable means to break bcrypt, which is why scrypt was invented in the first place.

It should be noted that what you describe with the stretching is essentially PBKDF2, which has been shown to be less secure than bcrypt.