Sounds cool - I cross posted this link to Tilted Mill
here.
In regards to new music (which Caesar 3 definitely does need as the original music is funny but gets irritating) - check out the open source soundtrack for the open source rts game 0 Ad here. This is an ancient military real time strategy project in progress similar to the Age of Empires rts series.
You can download the entire soundtrack for free - some of the music tracks sound like they could fit into an ancient Roman city building theme so this can be an option for music.
Maybe emailing the composer and asking which specific tracks were made with a Roman theme in mind may help?