I've never made my own deck
but I can't see why you shouldn't make your own, after all, aren't all the decks someones creative artwork.
I suppose if you have a deck you can copy the names of all the cards, so you'd know the meanings of them, then design your own pictures and images how you feel they should look.
I have a book called the Mythic Tarot workbook and it has pictures of the images with all the colour taken away. The object is for you to look at the cards, read the meanings and then, colour them in in the colours that you "feel" they ought to be. Your idea is just one step more, the images how you feel they ought to be.
and you never know, we may all be buying your artwork in years to come!.