So, you're asking....what you would own if you had the base game + every expansion?
Actually, aeoliner isn't too far off. Several of the expansions you'll be able to find only on eBay.
Ebay (most likely):
Games Quarterly
The Cathers
Crop Circles
I believe the other expansions are still in print and available.
http://boardgamegeek.com/boardgamefamily/2/carcassonnehttp://boardgamegeek.com/boardgame/822/carcassonneCurrently, my "Mostly Complete" Carcassonne set includes:
Base Game
Large ExpansionsInns & Cathedrals (2002)
Traders & Builders (2003)
The Princess & the Dragon (2005)
The Tower (2006)
Abbey & Mayor (2007)
Bridges, Castles & Baazars (2010)
Small Expansions:The River (2001)
King & Scout (2003)
The Count of Carcassonne (2004)
The River II (2005)
Games Quarterly Expansion "GQ11" (2006)
Cult, Siege and Creativity (2008, Rio Grande only, includes The Cult and a Cathars remake)
Der Tunnel (The Tunnel) (2009, Spielbox only)
Die Kornkreise (The Crop Circles) (2010, Hans im Glück only)
Die Pest (The Plague) (2010, Spielbox only)
The Phantom (2011)
Items I don't have, and I likely won't purchase:Count, King, and Cult (2008, HiG only. Repackaged as full expansion.)
The Catapult (2008)
Wheel of Fortune (2009, can replace base game)
The Cathars (2004, Spielbox only)
The Cult (2008, Spielbox only)
Are you looking for a complete, playable set? Or are you looking for completion? If you get 1 of EVERYTHING, you're going to be overlapping on several different tiles.
Ebay is the best/fastest choice for these:
Die Kornkreise (The Crop Circles) (2010, Hans im Glück only)
The Phantom (2011)
Still need the Celebration tiles -- only can get those in the 10th Anniversary edition.