There are some dwarf Canadian hemlocks - not sure if they are suitable for Missouri though.

- Tsuga canadensis 'Beehive' - a dwarf shrub to 3' tall and 5' wide, with the general shape of a spreading beehive
- Tsuga canadensis 'Bennett' - another dwarf shrub to 3' tall and 5' wide, with ascending then arching upper branchlets, preferring partial shade
- Tsuga canadensis 'Cole's Prostrate' - a groundcover form and bonsai alternative in partial shade to the prostrate Junipers, slowly to 1' tall by 4' in diameter, with the central stems becoming exposed over time
- Tsuga canadensis 'Gentsch White' - a dwarf shrub form (to 4' tall by 4' wide if never pruned, but half that size when sheared), with Spring tip growth that becomes intensely creamy-white in Autumn and Winter against the dark green background of the older foliage; must be placed in partial shade to avoid sunscorch; feather shearing is recommended to promote compactness and encourage more tip growth
- Tsuga canadensis 'Jeddeloh' - a dwarf shrub form to 3' tall by 5' wide, with a subtle depression in the center, and an alternative to Bird's Nest Spruce (Picea abies 'Nidiformis')

Here is a link that might be useful: source

I'm not aware of any. You might want to think about a broadleaf evergreen.

Dan

Yew.

Cephalotaxus species and cultivars. Some might not be hardy for you, but C. harringtoniana does well in zone 6 I have heard. Also, I have seen dwarf Cryptomeria cultivars doing fairly well in shade.

Ah, yes, I forgot about the Cephalotaxus. There you go Salix.

Dwarf Taxus is relative, and if not chopped then will grow past OP's specs eventually. Cryptomeria needs sun unless there is a new cultivar that is shade-tolerant.

Dan

Full shade is difficult :-) With the exception of yews (Taxus sp.), few needled evergreens will be happy or thrive in full shade. Partial shade is quite different and a good many, Cryptomerias and Tsugas included, will do very well under these conditions.

And while any dwarf conifer will continue to grow, often exceeding "typical" mature size guidelines eventually, yews are some of the most amenable of any conifers to pruning and can be easily shaped and scaled to a desired size without issues.