Adding unique marketing messages between certain products whilst using isotope/Infinite Scroll

Two thoughts:

1) Doesn’t isotope have a method for adding “stuff”?

2) What about adding a custom field or two, to the product and then use those to create an element before / after that product?

3) Instead of injecting the message via the loop just create the div / wrapped with some – id or class – and then use jQuery to fill those with something random.