Yes, I'd definitely be wary, but as alex.leon stated, changing your idea now will have to accompany twice or three times the amount of research in a very concentrated amount of time, to catch up with where everyone else is. You could do it but it would take a lot of dedication on your behalf.
Otherwise..... well...... What are you thinking, exactly, as your concept? WHY have you chosen the topic of incest, what do you want to communicate to your audience?
Definitely do not make it humorous!! I don't think it will go down well with the audience. A topic like this needs to be handled sensitively.
Maybe, just some ideas... Perhaps you could initially establish their love as beautiful, natural, blah blah etc, just a 'normal' intense love and understanding. Really make your audience empathise with the characters, throw in a complication which further draws your audience in and makes the audience want to see the couple stay together. Stress perhaps the significance of shared thoughts/mannerisms/interests, look into the idea of inheritance (ok, may be going off into a tangent), but I mean, look at what draws people together, and what repels them. The basics of what makes a good relationship. Lame, but with the incest thing, becomes more complex.
Then perhaps add the twist that they are brother and sister, (or whatever relation), after tying up subtle references that you've dropped throughout the text (Checkov's gun technique).
Which will make your audience question their beliefs: They were originally engaged with the characters, invested in their happiness, why should the fact that they're related even matter, if it's 'true wuv'? Is that what you're trying to show? Perhaps the characters do not even KNOW they're related? Perhaps only the audience finds out they're related, if you're doing some sort of post modern style. You could even do this through simple 3rd person. Perhaps the characters themselves would be opposed to it if they knew, but they don't, so is it a problem? Etc etc?
Just some thoughts that you can discard or not.
I suppose this is the definition of cliche in this topic, but I don't know what else you could plan to do with it? Unless the cliche is simply that incest is wrong/perverted, but if that's your aim, I don't see why you should be basing your major work around it, as that is the generally accepted belief about it, and you're not really challenging anything, simply affirming what society already thinks....
Let us know more about your idea. Don't get discouraged, although I may sound discouraging, I think it has potential, you just have to be careful.
... somebody please help!