I've enjoyed all of the small tarts I've had from Fox & Obel, and I believe they also make small pies. If I remember correctly, Lovely Bakery makes decent small pies, too. (They definitely have small pies, or at least they did last summer; I just can't remember if they make them in-house.) Alliance and La Farine both make tartlets, though they're at least two notches below Vanille, which I'd place ahead of Bittersweet.
Sorry I don't know about delivery from any of these places, and none of them are very close to you.
Fox & Obel
401 East Illinois Street
Chicago, IL 60611-4319
312-410-7301
Lovely Bakery
1130 North Milwaukee Avenue
Chicago, IL 60622
773-572-4766
Alliance Bakery
1736 West Division Street
Chicago, IL 60622-3212
773-278-0366
La Farine
1461 W Chicago Ave
Chicago, IL 60642
312-850-4019