Wouldn't it be better to use a Raspberry Pi. It would then be more portable and if you get a Pi 2 instead of a 3 you don't have to worry about internet since it had no wireless card. Also you could easily add an OLED display to it and program it to make it able to show transactions and wallet addresses
I don't think so. rPI2 + oled display + all the peripherals required would cost more than an old thinkpad. Also its a lot slower and less convenient to use. Also, you might not be able to compile certain wallets for ARM.