S.T.
high school is the period that strikes terror into homeschooling parents' hearts. so many of the kids in our homeschool co-ops and groups ended up in PS for high school because the parents freaked.
i'm really glad you're looking askance at the school-at-home option. you are absolutely correct- academically it won't be any better than just sending her. for kids getting bullied, or who are into the drug crowd or something, it could be an improvement, but for most kids it's just more drudgery, only now without friends around to share the mizry.
the problem with picking up a curriculum in high school is that they almost always assume a background with that particular curriculum that your kid won't have. it IS hard to come up with your own lesson plans, though, especially at the beginning.
so what i'd do in your situation is bite the bullet and get a curriculum, but remain open to the very real and present likelihood that you'll end up taking what you like from it and discarding a fair bit.
i really like clonlara and oak meadow, really any of the waldorf programs. but that's a matter of personal preference. singapore has a great math syllabus. we ended up using primarily saxon and barron's for math, though.
go over the curricula with your daughter and let her have a big say in it. that doesn't guarantee a program that she'll love, but it gives you a much better chance that a lot of it will work.
breathe.
stay flexible.
trust your kid.
the lack of accreditation in my cobbled-together curriculum really scared me for a long time, but it ended up being a total non-issue. my boys went to community college and got their associates' degrees, and then it's a moot point. neither had the slightest problem getting accepted at multiple universities. no high school transcript. no SATs. once they had their AA they were good to go.
good luck, and pm me if you want to chat!
khairete
S.