dealerships to buy units that can ONLY be used for demo
That is an unworkable solution to the problem, I believe. My local dealer carries the 4 japanese manufacturers and Victory, and they have a very large showroom with at least 90% devoted to vehicles, and only a small amount of gear/clothing. Typically they only have a single copy of any given model. They would have no room to store a demo version of each model of bike. By far the best way to accomplish this is for the manufacturer to bring a truck full of demo bikes for a weekend to participating dealers, moving from dealer to dealer. I have participated in this a few times, and typically I get 30 -40 minutes of riding per bike, on 3 different bikes, and it consumes about 2.5 hours out of my day. I have also done demos at the Progressive Long Beach show, and it was an awful experience. Waited in line for 2.5 hours for a 20 minute ride through downtown Long Beach, which is IMHO an awful place to demo a bike. The demo days at my local dealer took us on the De Luz loop, a highly varied, twisty at times ride through open land. I know you are fishing for ways to encourage your dealers to sell more bikes, and carry the cost of doing so, but at least as far as demo rides go, the only efficient way to do this is for the manufacturers to own this. I believe in this so thoroughly, that I will vote with my dollars (~$16K) for this option, see below.
As an anecdotal statistic, the last demo day I went to was done by Yamaha. I wanted to ride an R6, since I ride the track, and this seemed like a likely choice to replace my current track bike, and I wanted to ride the FZ-09 which seemed like a great choice to replace my street bike, when the time came. But I ended up having time to ride a third bike, but nothing in their lineup really appealed to me, but I decided I would try the FJR1300, just for kicks, knowing that would be the least favorite of the three. After the demos were done, I walked away with the opinion: I still want an R6, but it is definitely a track only bike for me. I did not like the FZ-09 much at all. And the next bike I will purchase IS the FJR1300, and since have saved about half of what I need to buy a new one. It is a fantastic bike and will fill a niche for me in both long distance multi-day trips and two-up riding. Would a Concourse or ST1300 better fill this niche? Maybe, but so far I have not encountered an opportunity to find out.