Despite what the pictures look like, there is nothing drafty about her build at all, she really is very light boned, I'm just terrible at taking pictures, I honestly am. I don't know what I did with the angle to make her head look like that in the pictures, she has quite a short, little head, kind of babydoll-ish but it looks enormous in those pictures. I really don't believe there is any haflinger there, and I'd be quick to think there was because they are so common around here, but she really just doesn't have it to me. Lots of breeds can carry the palomino/chestnut dilution gene. I didn't really consider hackney, she's definitely not full, but maybe hackney and shetland cross. She's dainty on her legs, but she has a pretty round, traditional shet.pony-sausage body, and kind of a thicker neck.
New Image, hehe my son fell head over heels for her when we went to look at her - I had really been looking for something a little bigger - that he could ride longer - but he fell in love and she is honestly the best darn little pony I've ever seen, she's awesome.
Smooth Trails, yes that is why I am guessing she is cart trained, although I have never tried to hitch her up. But she will trot at the speeds my gelding is cantering, her little legs just a blur, it's crazy. And like you said, she can do it all day and not break a sweat.
EastoWest - yes, she is very high stepping in her trot (again, under saddle. Not generally just in the pasture, unless she is showing off). Hee hee the big spotty boy in the picture has some pics posted on the this thread: Post pics of your drafts and draft crosses
I know it's not uncommon around here to see people covering small pony mares with mini stallions - but then while she is quite small, she seems to big for that. I don't know.