@MattRCan certainly add it here, but I thought it would just clutter the thread.
Several ideas have been adapted from MakeSupply Free Patterns. The base pattern piece is roughly 5.8" x 7.8" rounded rectangle. From this, you can adapt:
midori-style notebook cover (single piece of leather with a few punch locations, elastic cord threaded through to hold soft-bound journal inserts) this would be passport-sized
5x7 photo frame (two pieces of leather, one with a 4.5 x 6.5 cutout in the center for a photo to be slipped in, lace or stitch three sides to hold the frame shut)
Journal cover with pockets (of a similar idea to the first project, but multiple pieces to be stitched together to add pockets in the front/back)
Passport cover (two pieces, optional pockets, the inner piece has a cutaway in the center to slip the passport cover into)
Wallet (tri-fold, cut the primary piece in half lengthwise & stitch together adding extra pockets if desired)
The struggle I will have with the Girl Scouts is we often have everyone at camp - 5k Daisies all the way through 12th grade Ambassadors, and sometimes we have adults who participate and are vocal about quality or lack thereof of projects (yeah, I know the standard argument, but if I can anticipate the grumbling and counteract it, the program stands a far better chance of succeeding). This year, we had ~200 scouts at one week of camp. The class periods are 35-45 minutes long, making any "real projects" challenging. I don't know the budget per kid, but I'm guessing it's only a couple dollars.
My biggest struggles getting this off the ground are:
finding Girl Scout 3D stamps - they were made eons ago, and are just not easy to locate. GS-USA has no formalized programming to learn leathercrafting and our local council has no resources whatsoever to borrow. Sure, I have a collection of other stamps, but all the other kid programs (4H, BSA, etc, around here have custom stamps) eBay is going to cost me $$$, and usually only has the Brownie or Daisy stamps (I really want one single traditional GS Eagle, Craftool 8484, so I'm saving my pennies and will suck it up and buy it when it appears). As questionable as it is from a trademark point of view, I may resort to milling my own GS stamp.
tooling up for projects - Tandy kits are great, but not cost effective on a large scale (say 50+ kids). My hope is that with a set of standardized projects, I can get a set of 4-5 pieces, we can run a fundraiser, have clicker dies made, and cut pieces at one of the local machine shops (or maybe the high school or community college!) with donated time on their press.
Dependable adults willing to get up to speed on the skill enough to help at the activity. I'm not asking them to become experts, just learn - but that is always the case, isn't it? My hope is with a nicer project, maybe I can make a service area event for adults (or roll this into the Camporee that has adult patrols), and the adults will cherish their own handmade items enough to pass along the skills.
I have back-of-the-napkin sketches for the different projects, but not handy enough to post photos.
I do have a photo of the cutting die I'm experimenting with at the machine shop - I've never done leatherwork before, so this is all new to me when the scouts asked for it a couple years ago & I've been trying to get it together ever since. The tool is the big black chunk of metal, a CNC'd piece of steel (color changed after gundecking the hardening process), needs to be sharpened, but you can see the keyfob created by the first trial. The drill chuck has been modified with a straight steel 3/8" shank to mount on an arbor press and an internal bore milled out to make a flat transfer point for stamp shafts - this lets me do a quick, no-tool, stamp change at an event & keeps my set screws where I want them - secured properly in the ram of the press!