An author by the name of Tony Foale penned an article many years ago called "STEER FOR THE FUTURE", essentially a primer for alternative motorcycle front suspension systems. A copy of the article can be found here.
http://www.tonyfoale.com/Articles/Steer/STEER.htm
IMHO, telescoping forks, long the mainstay in current motorcycle design, have several design flaws making them a lousy choice for motorcycle front suspensions. Braking severely compromises suspension performance and steering geometry is constantly all over the map. All manner of gedgets and geegaws have been added over the years (dampers, anti-dive valving, supplemental air/oil reservoirs, etc.) to assist this fundamentally flawed system. I suspect Product Liability concerns have prevented manufacturers from straying too far from the current telescopic fork design.
Some time ago (15+ years if memory serves), Harley-Davidson was sued over their "shopping cart" steering geometry, used on Baggers and Road Kings to this day. A friend of mine was on the jury. A newbie rider with about a week's seat time on his new Electra-Glide (!) hit a big pothole on a gravel road, putting the bike into a big tank slapper which pitched him off. He was paralyzed in the accident, and blamed his injuries on the unconventional steering geometry (which puts the axle behind the steering pivot). My friend the juror told me HD didn't even try to defend themselves in the court case.
The newbie won the case and was awarded several million dollars. Harley never changed the geometry though, which is why the heavy Baggers are so easy to deal with at parking lot speeds. They did however limit turn-to-turn travel (which I found out about the hard way).