Found some interesting things at the GT40 forum
Cross ram intakes - Page 2 - GT40s.com Good reading, some of it.
It also seems like Moon (and also Inglese, but only as a complete package) has a croosram manifold that supports DCOE carbs/ TB's.
Mooneyes Online Store - Specialty Equipment Manufacturer, Speed and Custom Parts for Motorcycles and Automobiles
How would one of those work with 50mm TB's? Are the runners too small to support 600 Hp? The downside with this type of crossram is "how to get cold air into the throats"..? Two boxes and tubes from the front area is the sollution I can see...
Ok; let's have a look at those Aussie race- intakes.... Look great, work great- but the cost is 6000$ or so.