Backup all the files before you do any changes!

Settler information is in:
wherever civ iV is\Beyond the Sword\Assets\XML\Units\CIV4UnitInfos.xml

Search for "Settler" (Ctrl +F or whatever the search shortcut is for your editor). The tag that you want to change is 
<iCost>something</iCost> 
to 
<iCost>Ridiculous amount</iCost>  (in XML\Buildings\CIV4BuildingInfos.xml you can see how much wonders cost)

The info for the starting units is in: Assets\XML\Civilizations\CIV4CivilizationInfos.xml
Look for the structure:
[CODE]
                        <FreeUnitClasses>
				<FreeUnitClass>
					<UnitClassType>UNITCLASS_SETTLER</UnitClassType>
					<iFreeUnits>1</iFreeUnits>
				</FreeUnitClass>
			</FreeUnitClasses>
[/CODE]
Change the 1 to whatever.

Note: For the settler, I am not sure if it will work.