I just bought an Exocet, and own a E-mag as well, but even though I would not buy a third bow, if parts were sold separately, I would certainly consider buying additional parts for my two bows.
Like I said before, in an earlier post, it's an interesting concept, which in my opinion could be viable.
Of course, like everything else in life, there'd be pros and cons to selling parts separately, but I personally think that the pros would outweigh the cons, for all concerned.
How knows, if there's enough demand, it might be something Bill T. might consider. Time will tell.