In theory, yes. No one has made such a chipset, however.
This would be disadvantageous, due to the fact that the Athlon currently only has a 266mhz FSB, and cannot utilize all of the bandwidth of dual-channel RDRAM. This, coupled with the higher prices of RDRAM, and the higher latencies, makes it a less desireable solution.
Also, read AnandTech's excellent
nForce preview; it shows that there is very little difference in performance (when using an add-on video card) between the 420 and the 220, even though the 420 has twice the memory bandwidth. The 420, when paired with two sticks of PC2100 DDR SDRAM yields higher memory bandwidth (4.2 GB/s) than a dual-channel PC800 RDRAM system (3.2 GB/s).
So although someone could design and manufacture a chipset that used RDRAM for the Athlon, there is really no need to.