Pam!!
You didn't even mention that Dusty was also 'broke' to ride!! Dang-now I may have to do as you threatened-snatch some random kid from somewhere(one who knows how to ride, of course! to put on her!!
My grandkids are all 'WAY out in California-and probably, all too old/too big, anyway...I have a very small Western saddle-have to measure, but surely no more than a 12" seat-that was saddlemaker-made, and belonged to one of my cousins-along with a pony pad and, I think, still a pony-sized Navajo saddle blanket! Now I'll HAVE to at least try it on Dusty...
To go a bit off-topic--I have been lately driving Dusty more-found a great location only a mile down the road-a section of state land where a track has been bladed! Complete with a draw in the middle, where we can cross(here's where you need the breeching-it's pretty steep, but Dusty girl knows how to use the breeching, and lean into the collar going up!!) FUN, FUN, FUN!!! A friend and I were down there day before yesterday-she drives a Rhotens Little Dandy SON, a full(but honestly!) 34" gelding, with lots of"go", so he kept up easily with Dusty, but she was commenting with admiration on Dusty's easy, groundcovering stride! I got Dusty a beta harness, complete with the deep V breast collar, from the Carriage House, and LOVE it! The Bennington, which is mainly for Dusty, was supposed to dock in Houston day before yesterday; I am on tenterhooks for it to now get the rest of the way(took 18 days for it to cross the Atlantic; think they ROWED on the way over!!)-but have no way to estimate how long it'll now take to get HERE...anxious, anxious!!
As to the original question--I see no problem with a youngster of appropriate weight sitting on/riding, some of my 32-34" horses. However, a child small enough to ride one that size, isn't likely to be able to direct the horse on their own, IMO. I see this as the biggest limiting factor in riding minis. That, and getting a saddle that will actually FIT well enough that it won't sore the horse's back....as long as a good pad is used, and the horse isn't ridden for long, nor by too heavy a youngster, it's not a huge issue-but something to keep in mind.
On bareback pads...I agree completely that there should NOT be stirrups on one! I rode bareback almost exclusively as a kid-even after my dear uncle who got me hooked on equines bought me a saddle, I still rode bareback 'most all of the time! Later, I would take a mohair girth and an old cinch strap, and use this to hold just a saddle pad on--made a great 'bareback pad', out of stuff I already had--and anyone can do it!