Optifine has recently been updated with dynamic lighting, combining that with the new 1.9 offhand you can walk around with a torch in your offhand to emit light and never have to place torches.

Would it be possible to make the sigil of the blood lamp emit light for a similar result?

Considering this is an Optifine thing, and I don't think I am willing to add Optifine support, my initial reaction is a "no." In normal MC with almost every mod that has done so, this has ended up with a lag-fest.

Request Optifine to add a config. There is too much performance hit for us to be willing to implement.