I don't know if this is referenced anywhere, I performed a few searches in the bug/features part and couldn't find anything about it, so here goes :
When creating tiled clones, Inkscape automaticall uses the bouding box of whatever you're cloning as the fundamental domain for the wallapaper symmetry group.

1 - Is it possible to change this behaviour naturally by defining the bounding box explicitly ? If not, is this a proposed feature to be included in future versions of Inkscape
2- Is there an existing workaround ? I know I can fake a bigger bounding box by having a transparent object or something of the likes, but is there anyway I can have a bounding box that is smaller than the object itself ?

Thanks.

There is an option in the Tiled clones dialog: Use saved size and position of the tile, make sure it's ticked.

Create an object you want to tile, and make it in the size "small". Hit the Create button, then Remove button. With this you have set the symmetry box size to "small".
Now resize the object, in your case you need to make it bigger. If you want the resized object to keep the ratio and to grow equally in all directions hold Ctrl and Shift while resizing.
After you resize the object hit Create button again. Thats it!

It also works in reverse so you don't have to use transparent objects - create tiles, remove, resize object to make it smaller, Create again, and now you have space between the tiles (don't forget to keep that option ticked).

Thank you very much, most helpful.
Is there a way of using non rectangular bounding boxes ? Like, parallelograms ?

a bounding box is by definition a box that bounds the furthest extents of the object, so its always a rectangle.

I think you can use the shift parameters, so that if you have a parallelogram in your bounding box you can shift it per rows&columns and it will fit with the rest!
I'm not sure how this applies to other symmetries than just simple translations though, and I don't think this helps with more complicated Euclidean motions.

Simarilius wrote:a bounding box is by definition a box that bounds the furthest extents of the object, so its always a rectangle.

Yes yes, I know, I obviously meant the fundamental cell of the wallpaper group.