I toyed with this too, but I guess I have a slightly more diverse set of devices than you do. A few more weird voltages, and some things that expect mains. I looked into finding a DC version of their power supplies (e.g. the pico-box X9-ATX-500 to replace a conventional ATX PSU, tracking down DC versions of network switch hot-swappable PSUs from eBay) but decided it wasn't worth it. I just bought a stock LifePO4 power station. I found that I got most of the benefit [edit: measured in terms of runtime after power outage, not power draw while input power was available] just from switching to LifePO4 rather than from avoiding DC->AC->DC, and it was cheap and easy.