of this list, only the Amelanchier would amke my top five. What about Acer Griseum (the paerbark maple), Aralia Elata, Cornus contoversa 'variegata', any small birch, or the most gorgeous small tree I can think of (though notoriously expensive to buy) Schefflera Macrophylla.
For a large pot, I think Tetrapanax Papyrifera 'Rex' would look fantastic. This is not a tree, rather a big leggy shrub with monsterous 'prehistoric' looking leaves. Slightly hard to come by, but one of my favourite plants, and I know it would look incredible in big pot.