Growing direction of arrays at edit time

[ManuBzh]

I'd would find useful (may be it's already exists) to choose the editing growing direction of an array. It's used to be from left  to right and/or up to down, but others directions could be usefull.
Yes I can do it programmatically, but it's cumbersome and it useless calculus since it could directly done by the graphical engine.
Possible (and I forget about it) or already asked on the wishlist ? (I'm quite sure there's of one the two !)
Emmanuel