Guppie did you just say you had 8 mannequins? That's amazing. Post a screenshot, i'd love to see what a mog house of mannequins would look! Wouldn't that cost a whole lot though, since addional mannequins are a couple hundred thousand?
I was able to reach the "Powerful Light Energy" level (Moghancement Strength 51-100) with a full set of 8x Mannequins and an Adventuring Certificate (Reported to be Light +3), but not without the certificate.
This gives a calculated Light Elemental Strength of +6.
there is a quest for this, essentially you have to collect the 5 mannequin parts from garrison & BCNM (or just buy them at AH for ridiculous amounts of money) and then complete the quest and a woman will make them into the appropriate mannequin for your race and gender.
that said - i DEFINITELY want one of these, so once my ranger is leveled a bit we should totally get together and do the cloudy orb (lv cap 20) BCNMs, which are 3-person BCNMs and i'm sure we can find a 3rd LS member interested in this!
Yes, just like any other storage space, you can put items in the space provided by a mannequin. You can also put a set of gear onto the mannequin for display purposes, although the displayed set of gear still takes up storage spaces.