New Zealand has the Front Row factory and its various spin offs. There are training sessions to help train the coaches, who can then go back to their own teams. Lots of good stuff provided by the NZRFU as well. Props are key members of the team and good ones are highly valued here. School boys learn very fast that maximum game time can be made if they shift to the front row.
Super rugby players can be arranged to come and give tips to the boys at schools. I know we have had Highlanders props in at our training sessions, as well as former players running clinics. But we are lucky that we have had a few recent all blacks that are willing to come back in now and then (Ben Smith recently springs to mind). I remember Carl Hayman coming in that taking the 1st XV just before he got made an AB.
The last year or two, Kees Meeuws, former AB and a player who spent a few years in France, was available for training sessions. I took Junior along at the start of this season to the front row sessions being run in Otago. We had him and Super rugby refs explaining the new scrum engagements and how to scrum effectively.
On a personal note, I ditched the scrum machine long ago for training young props, I use it more when getting flankers and locks to bind on properly. I find more value in live scrums, as the angles are different from scrum machines. Plus most are built for adults, not youths, and they don't push back, bore in or try and pop you up. Skills that props need to learn how to counter.
I also believe that junior players are a little scared of the front row. I convert a lot of junior players each year to the front row, some sent to me from other teams. But that is simply because I played 17 seasons of senior rugby so learnt a few tricks over the years. First time Hookers in particular will pop up out of a scrum, grinning about how easy it was. Some players love the fact that they have a scrum and get to physically drive back someone who may well be much bigger than them, then they love the position. To be honest, thats why i kept playing for as long as I did. My inability to catch, kick, pass or tackle meant I wasn't much use elsewhere, but I could scrum and I learnt to do both sides.
Encourage junior players to have a go at Tight head and Loose head. they are quite different positions, with different angles and binding and challenges. Not too many players, even internationals can cover both sides of the scrum well.
One thing I have noticed on this forum is the referring to the props as pigs. I don't know if this is a common attitude in OZ, but maybe juniors pick up on it and get put off. Just putting it out there.
Just my 2 cents.