Mine would probably have looked something like this.
Basis is that the Airfix F-5 is split horizontally just above the bottom line of the fuselage, so two will siamese together.
Intakes are F-4, blended into the F-5 with lots of PSR.
I've used standard wings and tailplanes here, but an alternative would be Mirage deltas.
Twin fins is also a possibility.
double tiger by
Harold Smith, on Flickr