I have a problem. A friend of mine here in Norway owns a V-twin Excelsior with engine number T3048. He means that this is a 1912 model. This is all wrong again compared to your list. 3048 should be a 1909 model from your list, and 1910 was the first year with v-twins. Something is not right here. The register cover on his bike is not aluminum but nickel plated bronze.
I guess we just have to wait and see if other members are villing to unveil their engine numbers and years. I have already recived e-mails with engine numbers and production years from people that don't whant their bike ID to be published on this forum. That is perfectly OK with me. The important thing is to try to get a complete list that we can rely on.
I am looking froward to hear from you all on firstname.lastname@example.org