Hmmm... Thinking of Heddy Lemar?
Actually, Frequency Hopping Spread Spectrum (FHSS) is part of the original 802.11 standard. There are 79 individual channels, that are only 1 Mhz wide. Therefore, the total speed is only 2MHz. The frequency pattern is predefined. The only major difference from what you're proposing is that there is no counter jamming on the "unused" frequency.