Want to edit city maintenance costs

Are there any simple ways to mod the city maintenance costs without changing the difficulty level or cheating ?

I am playing on noble level, which I can win at, and on my own superepic speed on a standard map. But its annoying that I can only afford 2 or maybe 3 cities for all of the early game whereas the AI players can expand immediately and build 10-15 cities each until all the land is taken and this doesn't seem to cost them anything at all. They can afford to keep their research rate at 90-100%, build large garrisons, and fight wars. I have to wait until courthouse and currency before I can afford to take a 4th city. War is no fun I have to raze any captured cities so what's the point.

Once all their cities are size 6+ they just fly ahead in techs.

I would like it if I could be able to build six or seven cities in the early game too just as they can. I feel like a barbarian civ sitting there with my 2 cities for aeons.

There are several places the maintnenance values are defined, and yes even at the noble level the AI get's some "help" so you can address that too if you like

For the first instance you have the difficulty levels (CIV4HandicapInfo.xml), all of these bits are pulled from the Noble setting:

Decreasing any of these will make it easier
<iDistanceMaintenancePercent>75</iDistanceMaintenancePercent>
<iNumCitiesMaintenancePercent>70</iNumCitiesMaintenancePercent>
<iMaxNumCitiesMaintenance>5</iMaxNumCitiesMaintenance>

Alternatively you can get into the map size definitions (CIV4WorldInfo.xml), these bits pulled from the "standard" size:

Increasing this will allow you to support more cities before maintenance becomes a burden
<iTargetNumCities>5</iTargetNumCities>

Decreasing this can make distant cities easier to manage
<iDistanceMaintenancePercent>80</iDistanceMaintenancePercent>

This is similar to the target number of cities but allows for more fine tuning, a lower number will reduce the maintenance costs from the number of cities
<iNumCitiesMaintenancePercent>30</iNumCitiesMaintenancePercent>

And last but not least you have civic upkeep. The AI gets a big cut with civic upkeep so any changes you make here have a bigger affect on human players. It's all in (CIV4UpKeepInfo.xml) and it's pretty easy to understand, lower values will make the base civic upkeep values lower.

Okay, I can change those settings to allow me to afford more settlements

But is there a setting I can change so that the AI cannot afford to build so many cities either?

I went through and "reset" all of the modifiers for the player and AI at noble difficulty to 0 or 100 (whichever was most appropriate) and did the same for standard map sizes. The upkeep is higher and the AI has no problem handling it and expanding as normal despite losing their bonuses. I would imagine reducing the upkeep costs would make it even easier for them to expand. You can try going through the handicap file and removing any free settlers or workers the AI starts with, that seems to have made a substantial difference in their starting expansion, although once they get rolling they still expand quickly.