Not that I know of; it's been recently discussed in the thread about the limited release of the source code (and thus possible user-made patch, which might include things like this). Look for posts by YodaMaster.
In a very limited sense, perhaps - colonization tends to be cheaper if you have low inflation (duh) and also seems to be cheaper for areas with land connection to your capital (so if you were colonizing one large connected area then editing your capital to there might help, such as in the case of British North America or the Spanish and Portuguese settlements in the south).