The ginnalla is really fast growing around here...they can easily reach 10 feet tall and wide in 5 years...Now in your area it may differ...they tend to be very bushy and if left to grow big looked pretty shabby if you try to trim 'em they looked hacked since the branches are SO BIG...they do make great screens but I have had some dieback in shady areas making extra work and a few dead ones as well ...in full sun they should do fine as mine have ... remember if you EVER want to remove them ...after about 5 years they are basically a small tree and hopefully you are chain saw worthy cause thats what you will need... If I were you I would look into high bush cranberries... they also make great screens but are not so humoungous...they do grow about as fast and big in the same period of time but are easier to trim ...have no die back... and if you ever want to get rid of them you don't need a tree service to do so ...the branches just don't grow that large... the berries are purdy and birds like them ...supposedly you can use them as cranberries but I havent.I would at least consider them as a bit more manageable although the ginnalla is a nice TREE...David

Seattle has a big spreading one that fills up most of the front yard, others do seem to grow primarily sideways. Lake County nursery (and maybe a few other big wholesale growers) have new introductions on their web sites that grow up instead, not sure these are really Amur maples (and not another one of the subspecies of Tatarian maple) but since they are supposed to have similar autumn color it may not matter. If retailers near you are getting these now you may want to try one of them.

There's also Acer tataricum subsp. ginnala 'Durand Dwarf', "A compact shrub up to 1.5 m (5 feet), very densely branched, being a witches'-broom" (Gelderens, MAPLES FOR GARDENS). "Raised and introduced by Bernard E. Harkness, New York, in 1955" so it has been around awhile. However, "It is prone to sudden dieback".

And there's also 'Emerald Elf' and 'Compacta'.

Here is a link that might be useful: Searching -- Forestfarm.com

I've been growing an Emerald Elf four years now and it has stayed nice and compact. Its touted as having great fall color (like the species), but this has not been my experience. This is really the only complaint I have about it.