I think Med Night Mahout would be perfect for your girl and for what you are hoping to breed! He's an intermediate eventer (2 points off advanced) by Jumbo, 16hh so not too big, chunky but nice quality, huge jump, good paces - and the loveliest temperament, very calm and kind, which he passes on.
I don't own him or have any vested interest, just know him quite well cos he stands alongside my stallion at Cliveden.
If you're interested, I can PM details and contact numbers etc.