Why not model it in a spice program (eg like the free LTSpice) to prove y=
our
theory. Then build it.
There is a very good reason why I don't spice it up to prove it and then make it. I am very lazy. Although there are very few people in the world smarter than me there are also very few who can match me for being lazy.
Others have already proven the no input ripple SEPIC circuit. The rest of it, D from BC can be trusted to see how to do. There is good evidence that D from BC isn't nearly as lazy as me so I can let him to all the work. Being as lazy as I am, if he wants to take credit for the design I don't see myself bothering to do anything about it.
I hope this helps