Display of large number of markers in Google Maps V3

I am developing a large countrywide asset management application e.g storing all traffic signals, public lighting network, polyline pipe networks etc. I need to store and display these assets on google maps v3. The initial thought is to have one large xml file from which kml sublayers are displayed after being translated using xslt transforms. Is this a suitable way or is there an alternative noting the huge number of points that will require storage? I would also appreciate help on the api that would be needed