I think I get what you are asking. If you are looking to add the name of a GDB automatically, you must want to loop over a bunch of them, otherwise you'd just manually place the name of the GDB in the file name....
I can only think in code now, try opening IDLE and run the following:
import arcpy, os
location = r'c:\temp'
#Create Mosaic Dataset Parameters:
in_workspace = r'c:\temp\x.gdb'
coordinates = 'NAD_1983_UTM_Zone_11N'
num_bands = ''
pixel_type = ''
product_definition = ''
product_band_definitions = ''
number_of_loops = 6
for (dirpath, _, filenames) in os.walk(location):
x = len(dirpath.split('\\'))
dataset_name = (dirpath.split('\\')[x-1]).replace('.gdb','')
while number_of_loops > 0:
arcpy.CreateMosaicDataset_management(in_workspace, dataset_name + str(number_of_loops), coordinates, num_bands, pixel_type, product_definition, product_band_definitions)
number_of_loops -= 1