Actually, having 5 identical speakers is the most ideal solution you could ask for. Having three A50 or A52 across the front would perform nicely.
Placement issues would be my only concern as the 50 or 52 would be taller than the 122c. I suppose you could lay the 50 or 52 on its side, but they may affect the sound somewhat, but the 122c would sit that way anyway. You have to buy the 50 and 52 in pairs, which costs more than the 122c. Plus, there are not very many "50's" that become available as that is a retired model.
Placement issues would be my only concern as the 50 or 52 would be taller than the 122c. I suppose you could lay the 50 or 52 on its side, but they may affect the sound somewhat, but the 122c would sit that way anyway. You have to buy the 50 and 52 in pairs, which costs more than the 122c. Plus, there are not very many "50's" that become available as that is a retired model.