Vegan D3: Apparently So
Dr. Walsh said that they met with the company and that they were satisfied that the D3 in their product is vegan. Vitashine claims to get the D3 from lichen.
I then found a study that confirmed that at least some species of lichen grown in some locations contain vitamin D3:
Wang T, Bengtsson G, Kärnefelt I, Björn LO. Provitamins and vitamins D2 and D3 in Cladina spp. over a latitudinal gradient: possible correlation with UV levels. J Photochem Photobiol B. 2001 Sep 1;62(1-2):118-22. Abstract | PDF
The next logical question is whether vegans should go to the trouble of getting vitamin D3 instead of using vitamin D2. I would suggest that unless you are having problems raising your levels of vitamin D using D2, it is unnecessary.
One bit of advice I have is to take vitamin D with some fat to help increase absorption. I base this only on the fact that vitamin D is fat soluble – I do not know of any trials studying this.