The electronic structure of the high-Tc superconductor Tl2Ba2CuO 6+δ is studied by ARPES. For a very overdoped Tc = 30 K sample, the Fermi surface consists of a single large hole pocket centered at (π,π) and is approaching a topological transition. Although a superconducting gap with d x 2 −y 2 symmetry is tentatively identified, the quasiparticle evolution with momentum and binding energy exhibits a marked departure from the behavior observed in under and optimally doped cuprates. The relevance of these findings to scattering, many-body, and quantum-critical phenomena is discussed.