This is the Bob Marshall Sports Saddle, shown on several Icelandic Horses. A few of the Icelandics
pictured have long backs, some short backs.
There is no tree, so even if it's long on a horse, nothing is digging into the loins.
For the very short-backed Icelandic Horses / Ponies, a saddle with a shorter length
may be required. Check out the Saddle Fitting Guides
for more information about where the saddle should sit, and how to fit a saddle to
the static and dynamic back.