During the 2019 NG Meet-up in The Haguge, Netherlands, we visited Vivek Iyer and his charming wife. During the pleasant visit he gave me a monochrome-converted NEX-5N.
I have used it mainly with an IR filter for IR b/w. One lens that makes the camera small (it is already tiny, but a big lens would change its appearance) is the vintage 3.5cm f/1.8 W-Nikkor for the Nikon rangefinder line. The W-Nikkor is very sharp and matches well the NEX-5N. It also has no hot spots in IR.
From Oslo today. ARW file run through Mono2DNG, then tweaked in Photoshop. Focus is not perfect as the focus peaking on this Sony isn't very good. But it is OK enough.