Adam, sure thing. Here's the code. Note that this is written to be added to an Arc Toolbox and run from there. Arc Help on adding python script to toobox. I am also attaching the toolbox with script embedded if someone wants to just pick it up and use it. Suggestions gladly accepted, or modify in any way for yourself.
#~~~~Python script for quickly creating a water body vignette in Arc.
#~~~~Set up for use in an Arc toolbox.
#Get variables from dialog
workspace = arcpy.GetParameterAsText(0)
waterbody = arcpy.GetParameterAsText(1)
waterName = arcpy.GetParameterAsText(2)
base = arcpy.GetParameter(3) #long int
steps = arcpy.GetParameter(4) #long int
power = arcpy.GetParameter(5) #double
arcpy.env.workspace = workspace
arcpy.AddMessage("Creating buffers based on base and steps...")
#Complete buffer analysis using user-defined parameters
def waterLining (base, steps):
for x in range(0,steps):
#formula to calculate intervals between lines. is negative for Arc buffering inside polygon
distance = -(base*math.exp(power*count))+base
#same formula as above but positive for adding to attribute table.
distancePos = (base*math.exp(power*count))+base
arcpy.Buffer_analysis(waterbody, "buffer"+waterName+str(count), distance,"OUTSIDE_ONLY","ROUND","ALL")
arcpy.AddField_management("buffer"+waterName+str(count), "bufferDist", "FLOAT")
arcpy.CalculateField_management("buffer"+waterName+str(count), "bufferDist", distancePos, "PYTHON_9.3")
#Merge buffer feature classes to single feature class and delete individuals
fClasses = 
fcs = arcpy.ListFeatureClasses("buffer*")
for fc in fcs:
arcpy.AddMessage("Deleting individual buffer feature classes...")
for feature in fClasses:
arcpy.AddMessage("Finished creating water lines!")