StabbyJoe wrote:Cool! I'm going to get onto a little bit of materials investigation and try and source some cheap leather..
Try
eBay
That link is a search of the Australian ebay site for "(skin, hide)". The parentheses tell it to search for either term. Once you find a few, view the seller's stores to see more. Many of them are not listed with "skin" or "hide" in the title but simply "leather". You can imagine how many results you'll get if you search for just "leather". But browse the Crafts>LeatherCraft category too.
I don't know what price range you were looking to stay within but you can find a piece large enough to make several cases out of for about AU $20. Or a smaller piece for less than $10. Of course I have no idea what shipping is like but I would assume that it's not too extreme coming from AU.
If you want to keep it close to the way the peterson case is made then you'll want to use two different leathers. A thicker one for the outer shell and a thin supple one for the pockets so that they form to the tools. The outer shell should be 3-4oz (1.3-1.6mm thick) and the pockets (1.5-2.5oz (.75-1mm thick). Here in the USA leather thickness is described by the weight of one sq/ft rather than a measurement due to varying thickness throughout a single skin.
I haven't worked with any leather yet but I've been reading for a couple of weeks now. Found some good tips
here.
I'm about to tackle the exact same project next week and will be ordering some leather from ebay myself (in the USA however). Let me know how you get on with your project and I'll do the same.