Many of the Ph.D. theses now a days are being done though implementation of an idea rather than thorough research. So, I don't think that is a real issue for a Master's thesis.
If you like the topic, then go for it. Don't worry about what others have not done. There are various factors that may have contributed to unpublished results which have nothing to do with the topic itself, such as, non-motivation of the Ph.D. student or poor writing skills.
If you don't like the topic, you can propose a different topic to your advisor and unless you are being funded through that specific project (it doesn't appear like that this is the case from your question), he should most likely agree.
Good luck for your Masters and (hopefully) a Ph.D.
I like to blog about various topics ranging from education in IITs to social issues in India and US. All opinions and views presented here are my own and not of my employer.