For mono-red, here's my SB:

3 Goblin King
4 Relic of Progenitus
4 Chalice of the Void
4 Pithing Needle

And for my dream RGB build:

3 Krosan Grip
4 Chalice of the Void
4 Relic of Progenitus
4 Pithing Needle

I I board something in, I really want to see it, hence the mostly 4-ofs. Also, why do I rarely see Needles in Goblins SB's? It's a really strong card, as it answers a lot of the deck's problem cards.