Perhaps you like one of the backpack designs, but want a different color? A burlier fabric? An internal waterproof liner? Perhaps you want a climbing chalk bag made out of a bathmat, or a sleeping bag liner made out of your childhood blanket? It's doable.
Assuming I have enough to time take up your project, there is little I won't do. Best bet is to email me, ant@productionrunone.com, and we'll talk shop. Custom work can vary anywhere from you wanting a certain design in a certain color scheme, to pockets to fit your pens and cell, to my design and your fabric, to a completely new design of our combined imagination.