Diy?
Ever think of building one yourself? Guitar cabs aren't too difficult and a good wood supplier and average woodworking skills are all that's required. Most of the little extras (handles, corners etc.) are easily obtained on line. For a quick intro, check out Celestion's web site. Find a cab you like the sound of and measure the interior volume and build yours to the same volume, or just experiment. This works for guitar cabs: bass and PA cabs are a different and much more complicated story.
Most guitar speaker spec sheets have a recommended minimum enclosure volume and that's a good starting point if you aren't copying a favourite cabinet.