Linux (Debian Stable) runs great on it, and it has TrackPoint with a non-chiclet keyboard. And if you drop it on something, the something will probably get hurt more.
It doesn't seem "vintage". My previous one, made in 2009, also still runs Debian Stable well, including when running 3 different Web browsers and a couple other bloated programs at once.
I’m actually thinking of purchasing a X220 or X220T as a smaller, more portable model of the same era. To me, this era of thinkpad is the pinnacle of laptop design. Unsurpassed. Robust and practical.
I've also wanted to get X220, for more portable, but still matching keyboard. (I currently have some X200 units, with better displays than X220 usually has, but different keyboard layouts. They'll be a bit of work to sell, for the upgrade, since I'll have to replace the custom Coreboot that's on them.)
Can't you get a barrel connector on top of a modern GaN adapter? It should be much smaller!
You may need a circuit to negotiate the USB-PD, then to ouput 20V from that, but it should be possible.
It could even be a very interesting project: expose an artificial resistance on the barrel plug to simulate the Lenovo AC wattage resistor by matching what the USB-PD can deliver.
And a 7-year old machine isn’t necessarily obsolete either.
Apple uses those two words to mean specific things (vintage: >= 5y, < 7y; obsolete: >= 7y) as it relates to their support policies. Full support up to at least 5 years, some support up to 7, no support from then on.
Honestly, it’s pretty refreshing to be able to summarise 99% of a company’s product support lifecycle in such a small paragraph.
Make sure that you don't have another T520 lying around!