Has a carbon analogue of poly(dimethylsiloxane) been synthesized?
The comments to the original question do well to demonstrate that acetone polyacetal (or polyacetone; names in the literature vary, but these are the most common) is extremely difficult to produce by typical polymerization methods; this is mainly due to thermodynamic reasons, though acetal dimers and trimers of acetone have been produced at very low temperatures.1 

Polyoxymethylene is the polymeric form of paraformaldehyde (formaldehyde oligomers), which forms spontaneously in aqueous solutions of formaldehyde. The methyl-capped paraformaldehyde and polyoxymethylene would form if methanol is added to the solution; indeed, this is actually typically done to limit the length of paraformaldehyde oligomers. Polyoxymethylene, as a homopolymer, is quite stable and machinable, provided end-capping is performed; this is typically done with acetic anhydride.2




Burnop, V. C. E. Polymer 1965, 6 (8), 411-417. DOI: 10.1016/0032-3861(65)90025-X
Boyer, Lyndon D.; Sorenson, Wayne R.. Polyoxymethylene process. U.S. Patent 3355428, issued November 28, 1967.