What exact is the general definition of an 'aircraft without tails'? There are three major parts there, eliminating one makes one new plane, all means six; all of which have been tried.
In any case, the fact is that all of those ideas came from one source in time, military funding, and all designs made were restricted to that. Like the only reason a non-boom plane doesn't exists in the military inventory (yes it doesn't, including blackprojects) is because they had not thought it was possible or worth, so why waste money? Just get the objective and make money, that's the point of any business.
In the commerical industry there is no out-of-box thinking, it has and is continually being referenced to entrprenuership, which is a bad word cuz those people see failure as an experience while investors see it as your only chance. You can't play in this market, the military may give you a blank check, but not here. You would need serious backing and way before that, you need to prove yourself to others that you can do it. It's an uphill battle for out-of-box thinking in this industry.
To me, Boeing's happy fin or nose is not out-of-box. If I were in this industry, then there aren't many shapes or ideas left for Boeing or Airbus or anyone, having been in the box for so long, the BWB and SC
would have been the only contenders of that outside thought expression. All we can do in this specific subsonic industry is tweak: increase range, efficiency, size by use, etc. Nothing else. Everyone in here is going to be arguing with the younger generation about this fact of things getting boring.
Moreover, all of the current forecasts are that this tweaking will only go so far and soon (20-30 years) the demand WILL overtake the supply (technologially wise) = gridlock. We need something else by then and in order for that to happen we need to commit serious R&D within the next 5-10 years for whatever it is to come out by 2025.
The meaning of life is curiosity; we were put on this planet to explore opportunities.