Here are a few more I found that could work:
http://forum.thesims3.com/jforum/posts/list/375131.page - by Conorsim
Tech: EPs: WA, AMB, LN (complicated, see thread) * File size: 10MB * R-lots/C-lots: varied for player
Theme: Floating adrift the Simosapian Sea, Uncharted Island is waiting for sims to inhabit it - and to discover its deep, dark secrets. Will you choose the way of the Native Life, or Life as a Castaway?
http://www.thesims3.com/assetDetail.html?assetId=4851096# - Castaway Bay
Appears to only have base game and possibly pets, no roads, and 6 empty lots.
