They can also be pets or the like. I can easily see multiple trained bears under one or two humanoid masters.
I agree that golems should mainly be Elite. Similarly, so should a Warforged Titan or a Juggernaut. Anything at least Huge size should probably be Elite if not Solo (for practical purposes), including many dinosaurs and some giants. The high-end demons (Nalfeshnees, Mariliths, and Balors--the ones that in 1e were demons that had individual names, but no name for their species) should be elites. Dragon Turtles probably won't make it in the PHB1, but they should be solo. Ropers had better be at least elite--those things could get crazy in groups. Hydras, probably solos. Sphinxes, at least androsphinxes and gynosphinxes, make most sense as elites, IMO.