I found a very interesting page which noted some new discoveries for Pokemon Ruby/Sapphire before it was released
http://www.unseen64.net/2009/03/27/pokemon-ruby-more-unused-content-in-the-game/1) It seems that at first Pokemon Ruby/Sapphire was intended to be called AGB which stood for Advanced Game Boy (prototype name for GBA)
2) In the text dump there are several phrases which have been unused in the final game
i.e. This is sample message 1.
Welcome to the world of
POK?MON AGB!
We hope you enjoy this!
and the uses of the phrases 'GOLD' 'SILVER' 'DEMO1'
There are also some unused maps:

Possible debug room?

Closed version of the flower shop, only one person who says its closed
Also we already know but beta music is included in the final game:
* BGM from Route 38 & 39
* BGM from Pokemon Communication Center
* BGM from Generation 2 Saffron City
* BGM from Crystal?s legendary beasts battles
* Team Rocket?s Theme
http://www.unseen64.net/2008/05/23/pokemon-ruby-sapphire-beta-stuff/#respondAccording to that site apparantly Shellos and Gastrodon's beta sprites exist in the game suggesting they were originally going to be included in R/S but there must have been technical difficulties getting the sprite to change depending on where you were.


Edit:
Checklist:
1)
Add the R/S flower shop to the wiki2)
Add the unused blue map to the wiki3)
Make an article about unused music on the wiki4) Make an article about unused dialogue.