I reached the e-file limit of 5, If I buy another product under my wife's email address can I copy my return from the original software to the new product and e-file it?

There is no way to get around the 5 efile limit which is imposed by the IRS unless you file from a different internet location. It is not based on email addresses. 

You would not be able to transfer the previously prepared return to the new software.

Can I file at my neighbor's house?  

I'm not sure what controls the limit. If it is the internet address, it might work by filing it from your neighbors and using their internet.

You can always print and mail the returns. There is no limit on the number of returns that can be mailed.