The idea is sound but would only work on those channels that were either side and on the same Mux if you only had one tuner in the tv. The tv would just buffer the entire transport stream (technical definition here) and then you could channel hop within the channels broadcast on that Mux. The major expense for doing this on all channels you get would be the number of extra tuners needed for the different muxes required to be received. Plus the extra storage capacity for each stream you need to buffer and some software dev time.