Single driver loudspeakers

i don't think so. :)  However, you can build your own single driver speakers fairly inexpensively and try them out. For some they are magical and refuse to ever go back to multi-way. 

Here are some basic, but good quality kits.  If I wasn't up to my earballs in speakers here already I'd be tempted to build one:

https://www.madisoundspeakerstore.com/full-range-speaker-kits/

I've heard some fairly satisfying single driver speakers, but never one that met the criteria that you have laid out.

I should mention that there’s full range, and there’s full range. :) Some of the "full range" drivers actually use a mechanical crossover and tweeter, so you’d be really surprised how much has been done to stretch the technology.

When I design speakers though I try to get as much of the benefits of a single driver as I can. It’s easy to make a multi-way speaker and not at all easy to integrate the drivers so that they are not only measurably but audibly seamless. If you can tell where the speaker is, I call it a fail. This is not a problem single-driver (full range) speakers have to deal with. They do have to deal with the bass though. The usual compromise is to use a smallish driver, and rear horn or transmission line enclosure.

Still, I'm speaking outside my expertise. If you are really interested, come over to the full-range section in DIYAudio and you'll find many who will wave the flag. :)

Best,

Erik

Its not, best over all performance for widebands is the 6-8 inch consider fostex fe168esig