and Baptists do not accept the office of bishop as a supra-church position, but as a position within only one local church. -- what would then be the difference between a Baptist pastor and a Baptist bishop?
A single/individual "Baptist" church can elect a female and install her into any office it wants to, but this does not define anything "Baptist," for sure.
The Baptist church of which I am a member would never fellowship with or cooperate with such a church. A church that would so ignore Scriptural qualifications and install a female as "pastor" has plenty more doctrinal problems; having a female pastor would be but a symptom of much deeper corruption.
Actually, the word, bishop is a proper biblical term, we believe, for what most of our churches call "the pastor," or the presiding elder, if you will, of the local assembly.
It is characteristic of Baptist churches not to use the title "Bishop" for their pastor because it is felt that the unlearned might confuse it with the sense so often used in churches employing an episcopal form of government. Baptists usually claim to use a congregational form of government (I exclude myself from the congregational form).
Many Baptists these days are also shy to use the word elder for fear that some would take it in a presbyterian or Mormon sense, governmentally. This is a little odd, though, because up to 1900 or so, Baptist ministers were typically called "Elder Smith," "Elder Jones," etc. Signs in front of Baptist churches often said something like, "Elder Jedediah Hitchcock, Pastor" (there was such a man).
John Leland was a Baptist bishop/pastor of a local church in Virginia in the 18th century, and he was known as "Elder John Leland."
Today, very many Baptist churches indeed have multiple elders (multiple ordained ministers), but it is now typical to hear them called, "Assistant Pastor," or "Associate Pastor," or "Pastor of Evangelism," or "Youth Pastor," or "Seniors Pastor."
It is not necessary, in my view, to dance all around the terms bishop and elder without using them the way Baptists did 200 years ago and even more recently.