Have to agreed with Wes, nothing new about short breaks between sets. I believe Vince G. used that in some of his early training ideas in the late '50's. During the 60's and 70's most top BB'ers were using this principle for short periods. Most used it when getting ready for a show. Ideal for a super pump if that was your goal. Dave Drapper, Scott & Don Horworth (spelled wrong?) come to mind. All trained at Vince's gym (now a parking lot). There were also doing SS's, tri set's, giant sets, drop sets, etc big time around that period of BB'ing, with no rest between. 15 to 30 second between regular sets gave great muscle endurance considering most of those workouts could last from 2 1/2 to 3 hours or more. Pretty mild deca/D-bol was used but most relied on red meat, liver tabs and eggs (at least a of dozen a day..usually much more). Good Luck.
Side Bar: Most, if not all, the guy's who trained at Vince's gym always seemed to have better all around delt development than anyone else. This goes for the bicep bellies also (Scott curls?).