If you want accurate, then I'll help. If you just want loud, then a pro sound forum is what you are looking for. I think it is called prosoundweb dot com or something similar.
Hmmm, I wonder if you actually really really mean that! (This reply will test it out .... )
You want to build your own? Do you like the sound of cinema speakers?
Start with a digital active crossover - Behringer Ultracurve DCX2496 and we'll go with a 3 way using pro drivers and amps. Start with a professional compression driver and put it in a horn or waveguide (many choices you can buy). Drive the tweeter with a power amp that doesn't need much power, although in keeping with the craziness of the goal give it 100w. Now for the mid lets go for a 15" pro midbass driver. And for the bass some simple 15 or 18" vented boxes from say 35 - 200 Hz. As for amps - Behringer Europower is a good place to start for the mid and bass and perhaps A500 for the tweeter.
If you want to skip the learning curve, then consider options like Pi Speakers and Gedlee kits
Head over to AVSforum and do a search for the "No Quarter" loudspeaker that augerpro recently build.
I "built" (they are a kit) a pair of Gedlee Nathan 10 loudspeakers as my mains and they have me completely sold on the concept of high sensitivity constant directivity loudspeakers. They aren't even breaking a sweat by the time the volume is getting uncomfortable. The do require subwoofers to fill in the bottom end. I currently have four AE IB15s in the ceiling and a Maelstrom-x in the front corner to handle my bass needs.