As luck would have it a Gixxer forum member recognised the bike I'm looking to copy. From what I gather the fairing manufacturer the image is from (Airtech-Streamlining) started out as a guy making designs for his own bike. And he documented the build in a thread! That's going to cut down on the number of issues with the build I think.
This essentially gives me a shopping list to get the bike looking similar, knowing the parts combination works together.
Those wheels - Marchesini from the KTM Superduke 990.
That swingarm - a standard unit with a brace taken from a CBR900.
The forks - yep, GSXR750 '90-'95 units
Triple clamps - CBR929 units - they're drop clamps, allowing the shocks to be installed lower, giving more ride height.
Aaaand he used a GSXR1100 rear link.
So now I have a shopping list, some of which is going to be pretty hard to get. I'll start putting some feelers out on here and see where it takes me.