You guys should figure out how to implement a plasma tweeter: http://www.kickstarter.com/projects/studentrnd/plasma-speaker

Implement it so you get only nitrous oxide instead of ozone, then bring it to an audio show and demo it in a tiny hotel room with no ventilation. Play the Flaming Lips or something.

If only we can get all the guys who sell the snake-oil stuff in that room...

BOOM!

I would just build the DTQWT MKII:

http://www.troelsgravesen.dk/JA8008_DTQWT.htm

There's a very slim chance you will improve on that for the budget you have set.

These are the ones I want....so bad...

http://speakerdesignworks.com/Statements.html

or WATT speakers.

As far as speaker coherency, has anyone given thought towards implementing the same concept that Focal uses in their Utopia line-up?

That is, go spend a large percentage of your driver budget on a tweeter with larger range to try to drop the cross-over point as low as possible?
(then maybe pair with smaller reaching but almost equally quick midrange/sub-woofers + make up the remaining difference with a nice active cross-over?

I'm thinking that keeping all the information used for imaging and detail under one excellent-performing tweeter should be desirable, no? The only problem, of course, is if no such tweeter exists outside of Focal hella-expensive inverted beryllium domes...