I would just start small. If she likes all of what you said she likes, she'd probably be fine if you brought home some fuzzy cuffs or bound her with silk scarves or something--e.g., bdsm "light", the stuff they sell at any sex shop. Try getting them out one night, (don't just throw them on her), but once you're in the heat of it get them out and show her and ask if she'd like to wear them for you. If she does, (and maybe after a few sessions), discuss outside of sex what aspects of it she liked and if she'd like it to go further. You obviously care about her a lot, so make sure she knows that too--just be honest. Tell her you don't want to do anything that makes her uncomfortable, but she seems to enjoy it and you're wondering if it's something you can explore together.

Good luck!