A Prairie Fire crabapple might do, as might any other of the disease-resistant crabs. Other possibilities include Cornelian chery, Cornus mas; one of the fruiting viburnums,trained as a small tree; Mountain ash, Sorbus species; the other dogwoods, C. florida and C. kousa; various hollies; hawthorn, if cedar-apple rust isn't a problem, otherwise, forget it, it won't be attractive; smooth sumac, Rhus glabra, although it tends to sucker, like its cousin R. typhina, staghorn sumac, which is another possibility if you can control it.

Bear in mind that almost all plants/trees, no matter how drought tolerant they may be ONCE ESTABLISHED, have to GET established in the first place. If you can't or won't water for at least the first year (preferably for the next 2 years in long dry spells), then anything you plant will probably struggle and may die. It might live, also, but you should not expect everything to live without sufficient water for the first few years.

Since several of the species of serviceberry (Amelanchier arborea and A. laevis) evolved to grow in the South, they should be able to cope with the sometimes drought-y summers, once they are established! If you really like it, you might as well try a serviceberry as not. Watering it even a little, as long as it is watered well when it IS watered, should help. Mulching would also help. It may be difficult to find specimens of these trees, plus a few of the above mentioned ones, although since they are natives, Woodlanders or Niche, or Meadowbrook/We-Du should carry some of them.

I do think a Serviceberry would be just fine. The 'Robin Hill' cultivar appears to be a pink flowering one. I haven't heard much about it. You are certainly in the range for Serviceberry for 3 of the major ones: Amelanchier arborea, Amerlanchier canadensis, and Amelanchier laevis.

Here is a link that might be useful: Amelanchier distribution map