Hi,
I've the newest version of VirtueMart, I would know which files I need edit to customize the checkout (change steps order, css and put ajax), I thought edit /components/virtuemart/view/cart/default.php and delete calls to register and login and start from scratch (create call functions to BD, ajax etc) but maybe its very "bad smell".
I tried to find free plugins but i didn't find any. if u know free plugins, I would be happy to try it.
Thanks!.