Yes, the Sigma SD1 can do Live view without any physical modification or upgrade, at a recent event in Japan, Sigma representatives confirmed that the latest at a recent event in Japan, Sigma representatives confirmed that the latest SD1 camera can do LiveView
“We can add the feature, however the hard part is to ensure that the camera operate in a stable manner with that addition. However, this is a high priority for us and we plan to take this on as soon as we finish working through some of the issues that we have pending right now. When and if we actually make this happen is up in the air at this point.”
src- Photorumors | dpreivewforum