The number of signatures required for Pennsylvania statewide minor party and independent candidates in 2016 will be determined by how many votes are cast in the November 2015 statewide partisan judicial elections. According to this story, there will be three vacancies on the Pennsylvania Supreme Court filled in November 2015.
The existence of the 2015 judicial vacancies is good news for minor party and independent candidates for statewide office in 2016. If there were no vacancies, then the 2016 petition requirement would be based on turnout in the 2014 election, which will be far higher. In 2005, there were no statewide judicial vacancies, so the number of signatures in 2006 was based on the 2004 turnout. That is why, in 2006, the requirement was 67,070. If there had been statewide judicial vacancies in 2005, the 2006 requirement would probably have been 20,000 or so.
A reasonable guess for the 2016 requirement is 25,000 signatures. However, if the legislature eases the requirement in 2015, it may be less. It seems probable that one of the two pending ballot access cases in Pennsylvania, or both of them, will win, in time to improve ballot access for 2016.