Stripe, you said that window light is not good enough, but at my school, there is a ficus benjamina variegated form and it has survived 10 meters away from a window for 5 good years. not all bonsai can survive without window light, let alone window light.
Survive and thrive are two different things. I had a ficus by a window once, but then built a grow box with 800W cfl lighting. It grew a foot taller pretty quick over a few months, pruned it back, and now its time for the fourth cut back.
I also have had a juniper thrive under the same light for over a year and a half now. Junipers are strictly outdoor trees for everyone else..