Echinocereus coccineus 'transpecoensis' Van Horn, TX
Echinocereus coccineus 'transpecoensis' from Van Horn, TX is a disputed name from west texas. We still consider these echinocereus coccineus var. paucispinus but the oversea horticulturists insist its different. We will say this much, they are cold hardy to -17F in our garden. These plants differe from coccineus in that they have less spines and are more squat plants.
I do not guarantee these in a zone 5/6/7 because everyones growing conditions are different but this would be a good trial plant to grow in your cold outdoor garden. Try to plant outdoor 90 days before 1st hard freeze.