I don't know how much money you want to spend or how complex you want the build to be, but allow me to offer a simple alternative that I have good experience with.
I make portable speakers and exclusively use the Faital Pro 3" and 4" full range drivers. I personally think they are absolutely amazing, and exceptionally good value for money.
FaitalPRO | LF Loudspeakers | 3FE25
FaitalPRO | LF Loudspeakers | 4FE35
The speakers I have made have just used vintage boxes and cases. As long as they have relatively thick walls i'm not too fussy if they look good. The speakers have sounded great regardless.
Up to now, all of my builds have used the same amp - this tiny little beast:
PAM8403 5V Digital Amplifier Board 2 x 3 W Class D with Switch Potentiometer UK | eBay
I then power the speakers using either a USB charger, or a portable USB power bank. 3 watts a side really shouldn't sound as good as they do. They still amaze me when I switch them on now, and the people I have made them for couldn't be happier.
You can see my stuff here:
High Five Audio – Unique Audio Solutions
It would be fairly easy to make two cabinets and add the drivers. One of those tiny amp modules and a link cable between the cabinets. Or you could choose a higher powered variant and run them from a 12v adapter or the like. Bluetooth is available on many of the amp modules that you can buy too.
Cheers,
Jim