I've heard that for a quality cup of aeropress coffee, one should be only using single origin coffees. I was wondering what the advantage of using single origin coffees was over espresso blends when brewing with an aeropress.
The answer is quite simply: It's up to your personal preference.
Lots of things make a good cup of espresso; some people like (or think they like) single origin expensive marketing-buzzword-infused coffees, and others have found other roasts / blends that work just as well for them. You can use whatever you want in your aeropress to make a cup of joe that suits you.
As this question on Seasoned Advise suggests, there are some objective measures we might look at. Since and Aeropress (disclaimer, I don't have one, but I have used them while backpacking quite a lot) tends to extract a lot of flavor, a medium roast will probably prevent your coffee from being too dark, and still provide a lot of flavor. You'll also want a nice fine grind, which is generally what you want for any espresso machine.
99% of the coffee I drink is single origin since I roast my own and don't buy blends. That being said I also have an Aeropress I use 2 or 3 times a week to make coffee (I use a drip machine or clever dripper the rest of the time). What I have found is that any coffee I buy/roast that ISN'T recommended as a SO espresso tastes poor to me when brewed with my Aeropress. I have solved this issue for myself by no longer buying beans that aren't recommended as a SO espresso.
My untested hypothesis from this is that most coffees that would not do well as espresso will also not do well as aeropresso. While the resulting coffee from an Aeropress is not espresso, the brew methods share enough in common and the results are similar enough (not the same, but similar) that they have (my opinion) quite a bit in common with what beans do well when brewed in that manner.
Single origin versus blended don't mean anything out of the context of how they taste. It's possible to have a poorly grown and processed single origin that won't be great no matter how it's brewed, but it's still single origin. It's also possible to find blends that are done so for a variety of bad reasons (to produce a consistent, but not great taste, to reduce costs, etc) or blends that are done for the right reasons (to get a specific taste profile that may not be possible with any single origin, but IS great). There are great and less than great single origin coffees. There are also great and less than great blends. I thing that some folks have biases against blends because in the past they were most often done for cost or consistency reasons and not necessarily for the best flavor.
TL;DR I would likely recommend anything that should be good for espresso (single origin or blend) and high quality as a good candidate for Aeropress brewing.