Keep in mind that when David danced before the Lord he was wearing what was, in essence, an ancient middle eastern equivalent to undergarments. And while God did not condemn David for celebrating as he did in response to the victory and return of the Ark; you admit even still that it would be inappropriate in church.
And that would be my point. When we come together as the people of God, gathered around Christ's Word and Sacrament, this is sacred and holy, because we are standing before Christ-God Himself. I realize that this won't be the position of you or your church if you do not believe in the Real Presence of Christ in the Eucharist, but for those of us who do, we are standing before the very and actual Son of God, Jesus Christ, in the flesh, present for us in and under the elements of the Altar. In times past only the high priest of Israel could be so near to God, but for us we have entered into the Holy of Holies by the mediated work and presence of Jesus Christ, our Great High Priest. There can be nothing more sacred than this.
Worship should not be defined or determined by expressing our feelings to God, as though we are merely individuals doing individual things, this is only confusion as St. Paul says in 1 Corinthians 14. Worship should be defined by our corporate work as God's people, it isn't about "me" before God, but rather my place within the worshiping community gathered around God's works.
I would say that there was a time in my life, back when I was a Pentecostal and a member of the Foursquare denomination that I believed that worship was about expressing myself to God, and that "worship" chiefly constituted a certain portion of the service dedicated to singing and, even dancing, should one feel so moved emotionally. I would also say that in the years since then my understanding of worship has fundamentally changed slowly and gradually as I've come to understand the meaning of our sacred gathering together not as an opportunity to tell God how much we like Him, but as the meeting place of God, in Christ and the Spirit, in our midst; worship is ultimately for our benefit. God doesn't gain anything that He doesn't have already, but we are transformed and conformed, sustained and nourished by the life-giving Word of God and the Holy Sacraments. There is an interplay between the sacrificial and the sacramental.
I'm not going to tell you it isn't proper. But I do think it's worth asking yourself what would be proper when standing before Christ, enthroned in glory, in your midst. I'm not going to say dance is never an appropriate thing--but should it be an individual self expression? I think it's worth seriously thinking about this.
-CryptoLutheran