Re: Might be a worthy replacement
Not sure why you need to upgrade the W520, which has the blue "ThinkVantage" key and the screen light, with an otherwise identical keyboard layout to the 25. With 24 or 32 GB RAM, it runs just fine. It won't drive a 4K display at 60 Hz is all.
While the 700C was the first Thinkpad, the most iconic was the 701C which came out not long after. OS/2 was sweet and, of course, the butterfly keyboard. The main weakness of the 701C was the hinges. That would have been a fitting machine to honour.