There were discussions on KC-130. In fact during Red Flag, the PAF pilots even practiced ATA refueling and PAF's crew got to experience the KC-130. Not sure what happened afterwards on acquisition. Probably $$?
If the F-16's number will not increase due to JFT and other Chinese acquisitions, then you should design / procure CFT's or use the under wing ones, custom designed. I think the Israelis created some for their use back in the days.
KC-135.. based on the Boeing 707 airframe
The 130 is based on the C-130 airframe and has no variant equipped with a boom.