Proposed 3rd tier: Super Rugby 'A'
5-6 teams, each super rugby team plus a Barbarians team, based in Western Sydney(?) Or the Drua(?)
Format: Played throughout club/Super Rugby season on a Wednesday. Can play 1-2 games a night, giving broadcasters good value for money, outside of competing windows with the AFL/NRL (hold byes during Origin). Held at suburban grounds like Ballymore or North Sydney Oval. Partner with good event management, you could make it a fun night out for spectators. Imagine the ruckus of a double header at Sydney Uni on Student Night.
Players: Super Rugby squad players who either aren't selected that weekend and perhaps players who only have played limited minutes, eg reserve scrumhalf who came on in the last 5min of the week before. The rest is filled by top club talent.
Fulltime professional contracts will only be offered to those who play Super Rugby A. Genuine pathway, no more recruiting straight from club land.
Benefits: lowest cost, leveraging existing infrastructure from the pro franchises, existing fan base, genuine third tier standard with fringe super players playing with and against the top club players. Stan would surely be interested in expanding their rugby content for prime time midweek. Guaranteed Australian winner (which is really important apparently).
Downside: load management, this will have to be carefully managed, obviously, but not impossible. A player may be expected to play 3 games across 7 days, but this won't be a frequent occurrence. Not an uncommon thing in the northern hemisphere. With this level of autonomy, the season could run from the start of Super Rugby and go all the way through to Spring.