Forgive me, I stumbled across this thread while searching google. I have been fascinated with Middle Eastern dance for many years and recently began practicing the art form under a teacher within the last year. I am also a Christian involved in ministry doing film and drama for youth and young adults. I see a great number of things that Christians find acceptable in secular film and secular theater and unacceptable in Christian film or theater. I think this has also occured in the case of belly dance.
An understanding of the root of the dance and a dancers intentions on stage are crucial to whether a dance is 'immoral' or not. Just like I act publicly (and have played villains and immoral women publicly in theater and film) I dance publicly, however, I do what I can to make sure my dance is not intended to entice or seduce men. As one of the other posters said earlier, the dance was never designed for that purpose. There is actually evidence of women in Biblical times participating in 'belly' dances of various sorts (Moses' wife may have been from one of these cultures). Raqs Sharqi (as its properly called in one of its many forms) can be compared to Spanish folklorico or flamenco dancing. We find these forms acceptable even though they can be far more enticing or sensual. In the same way we have wedding dances to pop music and various cultures have celebration dances (the Greeks being a fantastic example), the Middle East had 'belly dancing' where women would get together and dance with other women. The men did different dances. It could very well be used in a wedding chamber but things did not change until the harem days of the Byzantine Empire, and even then there is little mention of dance for seduction.
One of the biggest wrecks to the credibility of raqs sharqi came from the movement in Turkey to cater belly dance performances, photos, and videos to the sex industry. Turkish dancing was already known for its 'anything goes' style, this just pushed it over the edge. That style still has not recovered its reputation.
Another issue that comes into play is how a venue treats a dancer. Are they an object (many 'dive' type resteraunts have this awkwardness in effect) or a person? Are they allowed to share the beauty of the dance or are they there to entice the men to come again? Are they a plaything or an artist? I found I was substantially more comfortable watching a group of dancers in a fusion dance exhibition at a local art venue then at a dimly lit, enclosed resteraunt with hookahs and pillow boots.
Christian dancers face a great challenge: portraying the beauty of the dance and not just using their bodies to get tips (this is even a challenging area as if you dance for tips, there's the moral choice of accepting tips in your belt or having a friend carry a basket, or even explaining the custom of showering the dancer with bills instead of touching her belt to give her a tip). We must be more careful with our choice of costuming as well. If you have a long torso that doesn't like to stay inside of t-shirts in the first place (this is my dillemma lol) then I don't see the problem of baring it for a dance. Simply compensate by making sure your legs are well covered and your bra is not cut too low. Many Egyptian dancers (in Egypt its actually a law) opt for either nude colored or black mesh body stockings that allow them to still perform rolls and other belly moves while being covered in a sense. Even something so simple as wearing long gloves or flesh colored tights and cheerleader briefs can help that line between being beautiful and being seductive.
A smile can also speak 1000 words. A dancer who looks like she's out to express her art, have a good time with the audience, dances with children, and doesn't play to men (always play to the woman lol) can portray a very family friendly show as opposed to the dead serious diva with the sexy slow music. A veil (for those not familiar with the dance this is a large silk cloth the dancer uses as a prop, not to be confused with Muslim or harem veils for the face) can be a huge help in modesty as well.
A Christian dancer also has a whole slew of options open in the area of showing praise to God in her dance. She can portray a Biblical character or dance to Christian music (fusion allows you to dance to anything from slow-classical to heavy metal so your options are endless). Even a simple gesture of bowing to the Father after you bow to your audience or praying before each dance can indicate praise to him. If you like Henna, incorporate a verse in Aramaic or a cross in your tattoo work.
My point is, the beauty of Raqs Sharqi is that its what you make it. All Christian artists in the secular world are faced with the challenge of maintaining our faith and performing our art. Put God first, celebrate that you can dance because of Him and are free to dance because of Him, and the answers you seek on what the lines of morality should be will be made clear