Well this is my take (grown up eating boerewors) but not having made any. We have a lot of local varieties of it; can be in thick or thin casings (opportunity to use lamb casings instead of pork if you want to avoid artificial).
I've enjoyed 100% beef boerewors so unless you've already tried using 100% beef, see how that works out for you?
If you have tried 100% beef and it's not working, what about it doesn't work? The texture, flavour, colour?