On amud beis, the gemara discusses issues that can arise when there are two men in the same city with the same name and one of them wants to write a get. The answer the gemara gives is that we can only write this get if both men are present. We also get into cases where someone fakes their name in a different city to procure this get.
It seems to me that these cases could be solved by having the husband sign the document. Signatures seem to be a sufficient form of identification, so why doesn't the gemara give this answer?
Although me'ikar ha'Din one may actually write a Get in his own handwriting (see Tur, Even ha'Ezer, beginning of Siman 17) a signature has no standing as identification in a "classic" Beis Din setting. Today there may be certain situations where a signature does have value in Beis Din, since it is accepted in general society, but a Get would not be one of these exceptions.
Shimon Brodie