in hong kong in the local camera circle there are quite a bit of imaginative oldtimers and camera hackers here to change old point and shoots or weird lens into your A7 or leica m mount. i seen a contax t2 38mm lens adapted to m mount as well.
i been thinking of taking a stepless aperture from a old jupiter 8 or some other broken old FSU lens to construct a working aperture with some point and shoot film cameras to adapt into a m mount (screw mount adapter).
i was thinking of adapting the yashica T with the zeiss 35mm 3.5 lens, and also a broken down 28mm 2.8 from the Gr1s as well.
currently i have two MS optical lens for the m mount; a 28mm 3.5 fujifilm lens from the super mini/ tiara, and a 40mm 2.4 summarit from the minilux.
for other mounts, i put a cheap OM to Nikon F mount on a old zuiko 50mm f1.4 with great results. It really handles great on my FM2n.