In that case, go as best you can, but definitely kilted. Button up the waistcoat, except for the last button, with a tie complimentary to your kilt; either primary color of the tartan or the primary stripe.

Here's the only pattern I know of for a coat; it'd be a pretty major, complex project; beyond my limited seamstress abilities:
Folkwear Kilt Pattern
Has anyone made one of these?