Hi!
I basically maxed everything relating to hardware, didn't select the I7 cpu though, I5-4300u has the virtualization support i sometimes need, and i prefer to have more battery instead of peak performance. This laptop could possibly use less energy under some workloads if selecting the I3 cpu, i'm not certain though.

• Hardware list:
• I5-4300u
• 8GB ram
• FHD IPS Display (1920x1080)
• 256GB SSD, Cache option disappears when you select ssd and/or 3g card
• touchpad with NFC and fingerprint reader (touchpad is a bit funky on the new lenovo's, it responds well and all after a few synaptic-configs in X, but it took me a couple of weeks to get used to not having ordinary buttons. And i haven't tried out NFC or fingerprint-reader, but they're a cheap addon)
• Backlit keyboard
• Large battery, 72wh + one small battery 23wh
• Intel wifi, 7260ac
• WWAN 3G/LTE card

With the large battery pack it weighs in at 1630grams.
i've written a basic guide to the tweaks i've done on a standard ubuntu install: Power saving stuff

Long post, but very relevant.

I recently got a Thinkpad X240 with the large batterypack (total of 96wh), + an extra batterypack of 23wh, have had it for 2 months now. It's running ubuntu 13.10 and i'm getting about 10-12hours of active usage from it daily. I also always bring the extra batterypack in case of emergency.

Power consumption and batterylife with the large pack.

• 2.8w (~34hours battery) - Lowest idle i've gotten it to (essentially nothing running, flight-mode activated so no radios or network, just logged in to gnome desktop, lowest brightness and leave it idle for 5minutes so it's doing nothing), but touch the touchpad or type anything and it drops by at least 4-6hours.
• 4-4.5w (~21hours of battery) - Normal idle with wifi or 3g, screen at 46% and a few things running (a couple of terminals, ssh, webmail)
• 5-8w (12-19hours of battery) - Normal usage when i don't really care, screen at 80%, wifi or 3g, lots of tabs, terminals, eclipse running in background..
• 12-16w (6-8 hours of battery) - Abnormal usage (for me). I need to be compiling, watch FHD movies/flash-video or other crazy stuff to get it to these levels.

Worst case scenario is 6hours of battery with the large pack, switch to the secondary battery (which i can do without shutting down due to the internal laptop-batter) and have 2 more.
Best case, (4-4.5w) where it's usable for troubleshooting via ssh and stuff means I have 21hours, then switch to the extra pack and have 5 more.

Best case scenario means I lower brightness to pretty low (which is still readable on ips screen, though not comfortable for extended periods of time) and don't browse the web (leaves mail, chat, ssh, serial console, wifi or 3g/4g), it reports a battery-runtime between 19 and 22hours, though I usually get around 16-20 hours. It heavily depends on what i'm doing.

Bringing down cpu and gpu consumption is essential to make it last longer. Lots of stuff are insane resource-hogs. (Flash, javascript, other stupid stuff waking up every millisecond) so here's a few recommendations to get you started:

• Suspend Tab - Firefox suspends the tabs so they're effectively not running after a set period (i use 30seconds), so i can have my set of 50tabs open, barely affecting cpu usage (and in turn, battery)
• Flashblock - I hate flash, causes insane amounts of work for the cpu.
• TLP - Powersavings for laptops, i've got everything set to maximum power savings all the time.

I really like this Lenovo!