I've seen shomen uchi nikyo ura done in two ways, the first being Responding with ikkyo omote, and the stance adjusts as the wrist comes up to the shoulder, lining everything up between nage and uke. The second variation involves ikkyo ura first, and then proceeds the same.
I am foggy in this regard, and maybe Aikido3D is a good aikikai reference to clear it up, but shomen uchi nikyo omote might be what you are describing at the end of your post. And if that is not what you meant, then as far as I have seen, shomen uchi nikyo omote looks a lot like going straight into ikkyo, but with a nikyo like interaction with uke's wrist. Hard to say, and only slightly easier to do, hehe.