Well, I do think that. At the moment alot of research is going up about the subject "talent", and the more we know, the clearer it becomes that talent isn't what we think it is.
For instance, some 40 years ago, a Russian psychologist wanted to test this, so he decided to train his 4 year old daughter in maths. His daughter, however, preferred chess, so he made her into a chess player. These days, she, and her two sisters and son, are the top of the chess world.
Whats even more interesting is, that by training and devotion, her brain turned upside down, and the part we use to analyse faces, is used by her to analyze the chess board, which enables her to figure out her next step within a few hundreds of a second, and she experiences it as "inuitive".
This experiment has been repeated (think the William sister, tennis), and I think (this isn't scientific proof anymore), that the more you train yourself in a certain skill, the better your brain organises things, and uses other than normal areas of it to complete the challenge, cause its more effecient.
One last thing, music, and most other creative arts, are thought up in the right side of the brain. The right side, however, is dominated in a certain level by the left brain, which limits the creativity. The so called "savants" often have left brain damage or malfunction, and that can lead to extraordinary creative skills. The brain of a savant does work in rather other way than a normal brain, but as stated before, the same thing, in a certain level, can be achieved by training, lots of training, devotion, and so on.
As a conclusion, I think talent is the time it takes for a individual to "configure" his/her brain to the task required. This, however, can be achieved by everyone, so in theory (well, my theory atleast ;) ), everyone can be Beethoven, some will just have try a little bit harder.