The latest addition to my hardware pool seems like a winner: Linux on Lenovo ThinkPad T450s.
A real world Tproxy implementation: Tproxy: Squid, Fedora and MikroTik.
A patch that enables suspend to both for in-kernel hibernation is now available: Linux kernel: Suspend to both. This patch has been merged into 3.6.
The patch to improve the hibernation/thaw speed of the Linux kernel has been merged into 3.2. More here: Linux kernel: Threaded LZO hibernation.