I agree with Mark – consider a multi-stemmed Amelanchier. Or how about Amur Maple? This can’t be in CO or you wouldn’t be considering an Eastern Redbud or Japanese Maple….
I’ve seen hundreds of Japanese Maples in small spots like this in northern CA that have thrived for many years, but they have many many cultivars available ranging from 5X15′ to 25×25’…depends on what you have available, but the space is definitely not too small for some of those smaller varieties.