This is a good place for lightweight camping gear.

This is a good place for articles and reviews on lightweight hiking.

Reconsider your position on sleeping mats. I think that some mat is useful for insulation from the heat-sapping power of the ground. You can loose a lot of heat through direct contact with the ground. Most, really good, sleeping bags will crush flat enough under you to be effectively useless as insulation but even a slim foam pad will provide a lot more insulation. You can get a 20" X 72" closed-cell (waterproof) foam pad that weighs only 9 oz (I don't know the metric conversions - or bother to look them up.). That foam pad can keep you a lot warmer than carrying an additional 9 oz of sleeping bag.

BTW a foam pad will also insulate you from those pesky pebbles as well. You might do as well by piling up dry pine-needles and dry leaves (if they are dry which might be difficult to find and difficult to keep that way)

Try this to save some money and weight at the same time.

For a really light pack using the sleeping mat as a frame you might look at this