You could have a look at the 4051 - Analogue multiplexer/demultiplexer (1-of-8 switch)
or an 4067 - 16-channel analogue multiplexer/demultiplexer (1-of-16 switch)
using a Hall based encoder or a position sensor, like the iC-MA or iC-MP from iC-Haus, the resolution can reach 8-, or also 12-bit(like the iC-MH). Here you find datasheet and application notes: http://www.ichaus.biz/keyword/Magnetic Encoder iCs