Nice work on the ol' Virago. You contemplated a single carb intake, which honestly you'd totally regret. If you're unhappy with the stock carbs, I am running VM38s on my TR1 and they are the dog's danglies. There's a 2in1 throttle cable for VM carbs and XS650-throttle-grips, which bolts up straight away and you'll need some new inlet manifolds UNLESS you skip the VM38s for TM38s as these are available with a throat in stock-carb outer diameter.
I have to admit I do like Hageman's Vinrago, but I think it would be very hard to build something along the same lines, which a) wouldn't be a blatant copy or b) look right. But then, that's what's called a challenge, right?