I'll say that I am pretty darn SURE that you will be seeing more of this kind of cart in BOTH miniature breed registry show rings in Country Pleasure(and similar) classes...although in AMHA, it may come more slowly than in AMHR, IMO.It hasn't 'happened' yet, and there will surely be some less-knowledgeable, and/or more tuned-toward 'fine harness' judges who will resist accepting them--but it WILL happen, I believe!
Now that there is FINALLY some genuine knowledge of driving other than 'fine harness'(high flashy action, minimal harness, show-ring-suitable-only horses, for the most part) 'penetrating' the ranks of at least SOME miniature horse carded judges, it can,and should, happen! Actually, that cart(see Rabbit's pics of it) is NOT proportionately large for even AMHA horses of, say, 32" and up; it is actually well-proportioned if viewed in the 'wider' world of driving vehicles. It's just that people are totally used to the little,low-slung(though this is not so evident when the horse is also 'low-slung, as are miniatures!) 'fine harness' type carts...that very kind of cart has been in use for many years for horses-the design/style did NOT originate with miniature horses. Driving one with a 'big' horse means not seeing much but the horse's behind...one reason they are basically only suitable for the show ring.
Also, there are now, finally, several GOOD choices of this kind of versatile and sturdy cart being made for miniatures,and able to be 'mass-produced'.From the UK, the Bennington and the Bellcrown(the latter now being made also in the US),the Lignite, American-made, and from Canada, the Pacific Smart Cart--are the ones that come immediately to mind--there may even be others. IMO, none of them is 'perfect' in every aspect, but they are all a BIG step forward, in a cart that can be 'dressed up' for the ADS pleasure, OR breed, show ring(wood or patent dashes, even lamp holders, etc.), yet work well for the CDE ring. Being able to invest in ONE vehicle that would work, and well, for ALL of these venues will be a BIG plus, IMO! My Bennington has quite a high seat, looks less 'traditional' than even the US Bellcrown or the Smart Cart, so might be harder for miniature breed ring judges to accept over here; I think the Smart Cart and the Bellcrown will find 'quicker' acceptance--but I feel pretty darn sure that acceptance IS coming and will be widespread before you know it. I already showed successfully in a wooden road cart; if I were shopping again for a cart to go in the show ring with, I would have no problem with getting either a Bellcrown US or a Smart Cart, or perhaps a Lignite....realistically, RIGHT now, it will still probably be harder to place, other things being equal, in one of these kinds of carts--but I personally feel that will be changing, and maybe, pretty soon!!
Margo