I was also going to suggest that you would feel welcome in an Episcopal Church, or at least all the ones I've been to. There are some fringe churches in the Episcopalian family that are either quite orthodox conservative or quite evangelical in flavor, but most tend to be open and progressive.
"The Episcopal Church strives to live by the message of Christ, in which there are no outcasts and all are welcome. Walking a middle way between Roman Catholicism and Protestant traditions, we are a sacramental and worship-oriented church that promotes thoughtful debate about what God is calling us to do and be, as followers of Christ. "
from the website:
Episcopal Church
That website offers a pretty good intro to the Episcopal Church.
Here's a little statement from the church I currently attend:
"We come together to worship God using the Book of Common Prayer, a gift of our English, Catholic, and reformed tradition. In it we seek expression to fulfill God's desire that we come into His presence and recieve His bountiful Grace in our lives. We invite you to worship with us...(some info about which book is the prayer book and which is the hymnal)...All who recognize the Lord's Body and come to the God's alter in faith, penitence, and charity, tor partake of our Blessed Lord's Body and Blood in Holy Communion this day, will be cordially and lovingly welcome."
Of course, you don't need to take Communion, I went through a time when I did not because it was not meaningful at the time for me. You don't need to say the creed. I went through a time in which I did not say it fully, and even now when I say it it may mean something different to me that the person next to me.
I would say that we are all gnostics in this sense, searching for the knowledge and truth that reveals God's Kingdom, whether we find it within the paradigm of the Trinity and Incarnation, or elsewhere.
My experience and understanding of the Episcopal Church is that no one is ever going to nail you down and ask you what you believe, unless you seek it out yourself to do so. There is a catachism but no one is going to force you to know it or even ask you what you think about it, unless you want to get married or baptized in the Church. Like Path of One says, with consideration and sensitivity to the paths of others, it is likely that you could find a smaller study group who would either share or at least respect your approach.
Even if you view things like the Trinity and the Incarnation all as metaphor, yet are comfortable with hearing about it in prayer, sacraments, hymns, and the sermon, I think you might feel right at home in the Episcopal Church. There's not a whole lot of other doctrine emphasized in our worship. You might want to take a look at the writings of Marcus Borg and Bishop Spong if you'd like to see how far we are able to stretch the paradigm.
A final note. In every Episcopal Church I've been in the outstanding theme is God's love for us and our mission to love one another. This is expressed through the Trinity, and I would also say that we experience in our worship and our lives in Christ. There is a lot of room for personal interpretation of the Bible--lots of room. A woman priest at the last church I attended said once: no one else can tell me how to read scripture or decide what it means for me.
As AdD said, how would anyone know you identify as gnostic. My father is an agnostic, or something like that. He does not believe in God at least, whatever that statement means to him. (I actually would call him a stoic if I had to express what he comes closest to in philosophy) Yet, he's been a very active person in the Episcopal Church in my hometown for years.
Best wishes,
lunamoth