Seriously, having a bit of trouble finding any. Most of the 2nd person romance with Rainbow stories I see have the reader as a pegasus... I kinda want a different angle on that relationship.

Here you go.
http://www.fimfiction.net/story/298089/dash-tries-to-win-your-heart

I should have specified where the reader is also a stallion, and preferably not the HiE variety. The possibility did not occur to me.

Pretty sure the The reader in both of these is a stallion earth pony
http://www.fimfiction.net/story/1827/number-one

http://www.fimfiction.net/story/1487/healing-dash