The T480 supports two drives by putting one in the 2242 NVMe slot (where the WLAN card goes if you have one; I just use my phone as a VPN+hotspot). You do need to find an NVMe m.2 2242 drive, but they're fairly easily found today. My personal T480 (I mentioned my work-provided one earlier) is outfitted as such: 1TB NVMe SSD in the 2.5" bay (Lenovo OEM adapter; if you buy the laptop with an HDD instead it comes with a SATA port there), 512GB m.2 2242 SATA SSD. You could put in a 2.5" HDD instead, though given how cheap SSDs are now I think it's probably unnecessary for most use cases.

As for keyboards--that's why I brought my machine to clients when I was a consultant, and specify the same laptop at my new job. ;)