...boring i know but looks bloody good on a bay,white is good but not practical,lol!!If i have to do colour for my lad it is blue(fave colour and he looks good in it)
What about a light blue, used to put my old mare in those colours and and she looked good but then wouldnt say she was a girly horse. Could try a yellow/lemon.
i love wellington green on bays, my last horse was bay and although a gelding looked very handsome in green, i dont think you have to worry about it being girly, if your for practical and more smart some people dont like colours like pink (im one of them, though i dont mind purple) then green
you could also go for a white sheepskin type thing??