You could look for Nyssa sylvatica 'Carolyn': "An outstanding hardy, healthy, female clonal selection from Professor Ed Hasselkus as a seedling from New Hampshire, of our native Black Gum-one of the finest trees for fall color. A luxuriant pyramidal tree with handsome, lustrous dark green foliage that turns a spectacular orange-scarlet in fall. Small oval purple fruits in late summer. Sun or partial shade and a moisture retentive soil. An excellent specimen tree for suburban locations."

maackia's recommend seems sound to me; however if you can't find that particular clone in these situations I always recommend contacting the New England Wild Flower Society. It wasn't what I was looking for during my visit, but I remember seeing a variety of native trees at their Nasami Farm nursery in western MA. They do list them this year. http://www.newfs.org/grow/buy-native-plants/plant-availability-list.pdf

'Carolyn' is probably going to be difficult to find.

Maybe you've already seen this thread:

http://forums2.gardenweb.com/discussions/2918843/experience-with-newer-nyssa-sylvatica-cultivars?n=4

'Red Rage' and 'Tupelo Tower' are hardier varieties that are becoming more widely available from nursery growers.

Did you ever find a northern source for tupelo?

No, Ed, but in all honesty other things took over my time this summer. It's a long term goal, not an instant gratification thing. I'll probably look some this fall as I visit nurseries.

I have a 20-foot tupelo that I planted as a small potted sapling obtained from Musser Forests (no special variety). It has gone through some nasty winters (including a couple where it got down close to 20 below) without any discernible damage.

After my Wildfire's 1st year in the ground when it died back to snow cover it has not lost a branch. We have had some solid zone 6 winters.

I bought a 5' Red Rage two years ago mail-order from Forest Farm out of Oregon. Last two winters have been true zone 5 experiences here, bottoming in the -16 to -18F range. The tree has not suffered any dieback.

Thanks to all who have added personal experience. We get to -17 to -20 most winters, and every few years we get to -22 or -23, so if there's any one who has one in zone 5a or 4b, I'd love to hear from them as well. I'll look for Red Rage and Wildfire and Carolyn.

I'd recommend against Wildfire in 4b/5a unless sited well. In recent years we've planted more than a dozen Wildfire in tree lawns (10' wide) in subdivisions, and so far they've all had varying levels of tip dieback every winter. A few were damaged badly enough that we removed them, others have recovered reasonably well. Perhaps with time as they become established dieback will be less of an issue. But we've also planted (in 10' tree lawns) Red Rage, Forum, and Tupelo Tower, and so far none of these has had significant tip or bud dieback (although borers and scale have been an issue on individual trees of all the varieties). Forum has had some frost cracking which makes me wonder about its adaptability in our zone compared to RR and TT.

Thanks, Dave. It looks like Red Rage and Carolyn are my two possibilities, then. I don't much like the narrow form of Tupelo Tower.

Tupelo tower and Carolyn came through zone 5 conditions in SE Wisconsin in a frost pocket without injury. The map says we're 5b but the thermometer says we're 4b. Wildfire has died to the ground twice and stopped coming back and JFS lists it as zone 6.