We report an angular quantum oscillation study of Tl_2Ba_2CuO_{6+delta} for
two different doping levels (Tc = 10K and 26 K) and determine the Fermi surface
size and topology in considerable detail. Our results show that Fermi liquid
behavior is not confined to the edge of the superconducting dome and is robust
up to at least T_c^{max}/3.5. Superconductivity is found to survive up to a
larger doping p_c = 0.31 than in La_{2-x}Sr_xCuO_4. Our data imply that
electronic inhomogeneity does not play a significant role in the loss of
superconductivity and superfluid density in overdoped cuprates, and point
towards a purely magnetic or electronic pairing mechanismComment: 4 page