GSI Outdoors makes an anodized aluminum 2.7L pressure cooker intended for backpacking. I've never talked to someone who has used it, perhaps you could be the first? :-D

https://www.amazon.com/GSI-Outdoors-Halulite-2-7-Liter-Pressure/dp/B0037D751O/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1503016391&sr=1-1-catcorr&keywords=gsi%2Bpressure%2Bcooker&th=1&psc=1