Ultimate DIY speaker design?

1. Linkwitz Orion+ (or ++). Believed by many to be the best speaker price no object provided you can live with the placement (really no different than a box speaker, although getting too close to the front wall is worse for bass and side wall less damaging) and output level constraints. Should be relatively easy to have a listen (try the http://orion.quicksytes.com user's group "seeking auditions thread). I love mine and haven't heard anything else more realistic.

2. Gedlee Nathan/Abbey + distributed bass. Earls designs are the only speakers a couple Orion owners have felt to be better. The physics make sense - more directivity will farther reduce room interactions and there's a lot more head room. After building favorite honey's recording booth I'll try the wave guide + large midrange crossed with matching -6dB angles.

Here's the link to the speaker mentioned by some above.

http://www.royaldevice.com/customita3.htm

This must be about as ultimate as one can get.

I'd like to see a home subwoofer based on these dudes.
http://www.mtx.com/caraudio/products/subwoofers/jackHammer.cfm
I like extreem stuff like this.The proplem with this hooby is most products have become downright boaring with a bunch of "me-too" copy cat wannabe making boaring stuff that's expensive and NO good.

6550 KCS offers a subwoofer with 31.5in driver.

Yes, there are some drivers larger than 22", but
the 31.5" 500W Fostex driver used in that sub is a little flea weight compared to the 370 pound MTX Jackhammer that is design to handle 6000 Watts.