This is never a good idea.
It's true that there is a handful of beardie owners out there that have successfully housed 2 beardies... But there are countless beardie owners out there that have done so, only to come home to a injured, dismembered, very sick pet, or worse dead one day even though they SEEMED to be perfectly happy together.
The truth is, no owner has ever really had complete success with this... They may think they have... but in all actuality, there is underlying problems with at least one if not both of their pets. There may be stunted growth, MDB, or just plain un needed stress on their pets that they have failed to recognize.
People see hatchlings in pet stores all huddled in the corner, laying on top of each other and think it's so cute... Most times they are all from the same clutch, and this is a very early sign of dominance, and future problems to come. those little ones laying on the bottom, will be deprived of much needed UVB rays, most times not able to eat enough because the more dominant beardied will fight to eat first. It's simply survival of the fittest and it will happen in every single home.
As a pet owner, it is YOUR responsibility to ensure your pets are receiving the best quality of life possible... Offering them a lifestyle sub par to what they would have left alone in the wild in unaccecptable. You could kind of compare it to a human being locked in a jail cell with a big scary guy all day and night telling you what to do and when to do it... it's just not fair.
If you are worried that by only having 1 beardie it will become lonely? Lonliness is a warm blooded emotion.
Bearded dragons are solitary animals. They do not live in colonys as some will say. they live alone. They come together to mate, and the move on. In captivity they will be more happy not even knowing other beardies exist.