Could the use of Elvish Spirit Guide allow access to green mana with lesser difficulty, or would that take up slots better occupied by other cards? It seems to be the latter; have you tested ESG at all?
ESG is probably on par with Lotus Petal, since blue mana is sometimes good to have early. Either one is definitely worse than Lotus, which there just isn't room for. Maybe in a budget version, but even there lands would probably be better.
Black Vise and mis-d have been amazing. Now I have to find room in the side for more BeBs, Swords, and Crypts.