Yes I have but only once I don't have much time all of my other custom ponies either have their head off some of them don't even have their hair pulled out completely or cutie Mark taken off but I have made a custom before and completed it her name is twisty Lou I'm reorganizing my pony room so I have no idea where she's located or I would take a picture for you
Not really? As a kid I wanted boy ponies so bad that i turned fakies/horses into either big brother ponies (which I could not afford) or the boys from FIM. 11 year old me would be happy that they did end up making more boys.
Other than that, just painting on my g3s or giving them "eyeliner" (luckily with magic marker, most did come up)