I would strongly suggest Glockenklang, Soul or Heart rock head, depending of your power need.
Like K said, not exactly flat but will let you ear the sound of your bass with a bit of warm. 5 bands eq voiced exactly where you need it (bass blooming, low mids punch, mids to cut through the mix, highs for cizzle, and extrem high ends to refresh your strings).
Then a Quattro US 4 ohms or a Double US 4 ohms also from Glock and there you go.
Now that I've seen a bit more equipement brand, I can see why Glock is amazing also in its bullet proof construction .
Don't want to offense any body but even a high end cab like a Epifani looks like common stuff beside a Glock cab.