I have trouble waiting 15 years, feel really bad for the Americans having to wait another 10. Us Canadians will keep our cars in good shape to make it easy for you to import from here once they turn 25 rather than sourcing them from across the pond.
I admire your commitment to build one yourself though. A local guy up here just built a B7 RS4 Avant from an S4 Avant shell. It is amazing as I'm sure yours will be.