>>3115155Small and light is no problem, you can easily get ball heads that featuring a lower volume (never mind a more rectangular one better matching typical bags) and smaller weight than a typical Gorillapod.
Only "flexible" is not something you can get AFAIK. I say it is because it's really not such a good solution, but I guess you disagree. Still, I don't think it exists and there may not really be a market for it.