memoire and Ritani both make single prong settings like the you posted that is made for an e-ring. pearlmans carries both designers and you can see pics on their website.
Not an expert, but am interested to know how this could be made into one that would fit a 1.6 rb....I have seen an e-ring similar worn by an old classmate. Loved it.
It it is definately possible to convert your existing band to an ering. Whether it is in 14W or platinum, you should have it laser welded with a platinum "peg head". You will have to drop a diamond, or use the blank spot on the back of the shank to insert the peg. The peg head can be soldered or welded directly into the hole behind one of your existing diamonds.
Your center diamond may stick up a bit; make sure the prongs are nice and smooth and they dont catch on sweaters, etc.