Not exactly sure what your question is.......do you want to know how to make a red velvet macaron, or are you looking for advice on how to make a more consistent looking red velvet macaron, or are you looking for suggestions of other flavors of macarons?
I think since "red velvet" is a style of cake and not technically a standalone flavor (the way that vanilla is a flavor, or that key lime is a flavor) you might just do a red macaron shell and perhaps use a tangy filling (because red velvet, aside from the huge quantity of food color used, started off as a buttermilk cake with a little cocoa that was supposed to give off a slight reddish color when baked. IMHO it's morphed into a red cake with cream cheese frosting and sometimes toasted pecans added to the filling. It's taken on a life of its own really.) So perhaps go with a cream cheese filling (like you would use on carrot cake) or maybe a creme fraiche or sour cream ganache filling.
I use mascarpone in my red velvet cake instead of cream cheese. I attempted a "red velvet" macaron last Valentine's Day. Meh, you can't really get that flavor in there. I added cocoa and red color, piped them in hearts and filled with cream cheese/mascarpone filling. Basically just red macarons.
There is a red velvet cake flavoring I've seen around. Have no idea what it tastes like, but it might work for the filling?