Gas powered camping lights are no longer needed, along with the associated fire and burn risk. It is quite easy to get 12volt lighting for your campsite. There are several companies who provide LED camping light kits that include everything except a battery. For a Cuboree/Jamboree you need to be able to run your lights up to maybe 10 Metres in all, so you can light both your kitchen and dining areas. Some kits (from Rainbow Lighting for example) even have batteries built into each light fitting so they can be placed anywhere, and just reconnected to the charging panel during the day. This is the other feature of many lighting kits - a solar panel to recharge the battery. Some kits include a panel, while others are designed to run off your car's battery and will need a seperate charger. However in reality, to run a standard LED lighting set for a 4-night Cuboree, you probably will not need to recharge anyway. While 12V CFL lighting is sometimes a little brighter, the advantage of selecting LED lights is their VERY low power usage, allowing your battery to last longer. (For example, KORR lighting promote their light kit as being able to run up to 100 hours before your car battery is flat).
How much should you expect to spend? Most kits are in the $200 to $300 price range, and one of them will last your group at least several years. The most recent deep cycle batteries can last 10 years too, so overall it is a very worthwhile investment - and no more gas mantles to buy (unless you are covering the relevant Scout Campcraft test).
What you will need if you do not buy a kit:
Another option is to buy half a dozen portable car LED work-lights from your local car/discount store, as well as a couple of multi-plug "lighter-socket" adapters. While the worklights usually have a reasonably long cable, buying or making a few extension-cables with the same plug/socket combination would also be a good idea. Then a short adapter cable with aligator clips for the battery and a "lighter" socket completes your set.
To safely transport your battery, you should build a timber carry box with hinged/removable lid and rope handle. A carrying box for the lights is also needed, to ensure they are not at risk of being crushed and broken during transport. Your batteries should easily last a weekend camp, and probably the 4 nights of a Cuboree before needing a recharge, though use a solar trickle-charger can also be implemented during the day if one is available. The rest of your light kit should be stored in a suitable sized box as well.
Here are a couple of sample kit pics, to give you an idea.
While not recommending them, feel free to check their websites.