Pebbled is fine for structured bags, just let Marco know how structured you want the bag and he will tell you if it can be done (it depends slightly on the model). In my experience, structure does not add much weight.
I used to worry a lot about backings and structure. I pestered Marco for details (how stiff? how thick? how heavy? How do you do it?). He patiently answered all my questions. In detail. Here is a clip from one of his replies (this man has the patience of saints):
Depending on leather thickness we use several different kind of backings. Microfiber, for example, is available in 6 different thicknesses. It can happen that the same kind of leather, used to produce the same style, can require 2 different kind of backing: an Aura in black Verona could require a 0,4 millimeters microfiber and an Aura in dark green could require a 0,8 millimeters microfiber. Weight difference between the 2 would obviously be small, say between kg. 0,05 and kg. 0,10, but even those details have to be considered.
A Soulmate in Merinos usually requires just a mm. 0.4 microfiber. Some leather parts have no backing at all on Soulmate. Bottom usually requires a bit of thicker microfiber while strap requires a flexible texon (even texon has several different thickness).
In particular situations it can be helpful to use suede lamb as backing and more rarely we use a special thin cardboard for handbags. This just to let you have an idea since possible combinations are probably infinite.
Finally I realized that I did not need to ask about "how".
All I need do is
- describe what I want
- ask Marco whether it is do-able
- ask Marco if he thinks it actually is a good idea!
Makes me want to lean forward to smell the leather. 
