I've had this idea for a mod for a while now. I know there are some mods who already do this, but I haven't seen the one I am thinking about.
basically it's the starter chest from vanilla minecraft, which you get when you spawn a new world with some items to help you along in the beginning
but instead of it being a chest, I would rather like it to be a bag that you receive when you spawn/join a new world.
the bag would be like the dartcraft loot bags, meaning you can take items out, but can't put items back in, and when you take out the last item out of the bag, the bag will automatically delete itself
through a configuration file you'll be able to choose what items/tools will be in the starterbag, this would also move any other starter items you'd get on world creation/loading to the starter bag (for example the beginner book from Tinker's Construct and the guide from Rotarycraft)
this way you can keep your inventory pretty small and you'll be able to gather more items in the beginning, as you can leave the items you won't need right away in the bag.
some things that you could for example put in the starterbag are the guides from mods. you'd only get 1 book from each mod, and if you lose it it'd mean you'd have to craft it yourself the next time. I always find myself not beginning with mods because I don't have the guides from them. but if I were to have those guides upon world creation/loading, I'd start with those mods sooner.
you could also put in some food items, torches, stone pickaxes/shovels/axes/swords, or perhaps some Tinker's Construct tools like the hammer or excavator so the player can build their base faster, but to not make it too easy, the hammer or excavator would be made completely out of wood, so it wouldn't be the most efficient tool to use.
I know slow was talking about similar like this a while ago, but both slow and the mods who add something similar to this add a chest, and a chest can't be picked up without losing it's inventory... and having all those items/tools in your inventory decreases the amount of resources you can gather while you're searching for an area to build your base
this mod could also be used for servers to give a book to their users with things like server commands and rules in them.