How about a Lisa set to sync? If you feed that with a arbitrary signal at gain .5 mixed with a step set to a value of .5, (which would turn a signal from range -1 to 1 into one from 0 to 1) you can set any mapping you'd like. Filling that LiSa with a line from -1 to 1 would get you your original signal back, a "staircase" would give bit-depth reduction, etc.

Multiple mappings could be made and by changing the loop start and end these could be selected.

Shreds might be more versatile as those also give you easy access to modulating bit rate in addition to depth and to get a resolution equal to double floats you'd have to use a very large buffer indeed... but then shreds are often expensive and the code gets messy looking, IMHO.

Yours,

Kas.