Forums / Discussion / Meme Research

I let Google show you all the examples you need:
https://www.google.it/search?q=pinkie+pie+and+surprise&source=lnms&tbm=isch&sa=X&ei=DWBIUuqVK6rl4QTluYDIBQ&sqi=2&ved=0CAcQ_AUoAQ&biw=1366&bih=600&dpr=1

Here are a few ones:

A popular combination, but nothing out of the ordinary that requires documentation.

I would agree with RandomMan. It's certainly known within the fandom that (forgive me if I'm not up on my broniness) the concept of Pinkie Pie was based on Surprise from the first generation (one before the current generation, at least. Pinkie was originally designed to be a pegasus while Fluttershy was going to be the earth pony.)

So while there's a lot of instances of the comparisons, I wouldn't think it to be any more noteworthy than the Wii Fit Trainer being compared to Chell or Korra.

If that trio doesn't have an entry, then I wouldn't think Pinkie Pie and Surprise would. And subjectively (Blech…) it doesn't strike me as being suitable for an article. You could mostly say that the two share origins and a lot of fan art came of it, but that's about it.