What are some unconventional ways for a woman to express her submission?
I took the liberty of relocating your question here

An interesting question... one I am having trouble finding a clear-cut answer to.
Are we talking lifestyle D/s or bedroom/kink D/s? What is considered conventional? Does conventional mean the stereotypes of D/s? Why would a behavior or act be considered unconventional? And by whom?
I can only speak to the behavior of a 24/7 submissive. I suppose by "conventional", you mean the usual... obeying, kneeling, serving, offering her body to him, etc. Perhaps by unconventional, you mean a variation of all of that, a deepening of that D/s dynamic. A submissive who thinks about and understands fully what submission means and entails, and then offers it to that one person, may be unconventional if compared to some subs who have but a cursory understanding of it all. A submissive asking for protocols to be set out for her, may be acting unconventionally. Instead of the Dom bringing it up, she asks for it to be put in place. Instead of the Dom manipulating her into submission, he waits to see her develop and grow her submission till she begs, through words or through actions, to submit to him. Being inked for him, massaging him without him asking for it, going past what is expected of her, e.g. her studying the lifestyle... all ways maybe unconventional to some. A sub who begins to engage in writing out D/s stories, to give voice to her submissive soul, is acting out of the D/s norm. A sub who considers a major life adjustment for her Dom, and finds happiness and purpose in her now new world is doing more than just serving him his meals or falling to her knees.
For me, submission is submission, and every submissive has their own way to express it, based on who they are, their character, their past, their expectations, etc. As long as everything and anything the sub does, is for and with his/her Dominant in mind, it is an expression of her love and bond to the Dom. What may be considered unconventional to some, may just be the norm to a couple.