Technically any bonsai can be grown indoors, but many species require highly specialized care with grow lights and temperature/humidity controls.
The reigning consensus among bonsai growers and in bonsai books is that junipers are terribly suited for growing indoors, and the conditions you describe would agree with this. Most junipers require full sun (6-8+ hours a day of direct sunlight).
The plants most often kept as indoor bonsai are tropical, ficus being among the most common, along with dwarf bamboo varieties. Ficus are very difficult to kill and can survive in bright, indirect light as you mention. A ficus would definately be my suggestion for an indoor bonsai, especially if you're looking for the typical aged-tree look.
I can't suggest any one in particular, but you may want to pickup one of the many books dedicated to growing bonsai indoors (go to amazon books and search for 'indoor bonsai'.)