The trend of cell miniaturization in concentrator photovoltaics (CPV) - currently in mm-scale and motivated by efficiency improvements linked to reduced series resistance - begs the question whether fundamental energetic considerations limit ultra-miniaturization. Mitigating factors subsume the busbars and metallization grid, the contributions of which embody subtle tradeoffs and vary non-trivially as cell size is reduced - evaluated via a distributed circuit simulation model, with some supporting experimental evidence. Concurrently, the influence of cell size on how metal grid design can lower series resistance is assessed, prompted by micro-concentrators that completely eliminate grid shadowing and allow far greater metallization coverage. (C) 2011 Elsevier B.V. All rights reserved.