I suspect that Taurus will weigh in at 7 kilograms or more. If you can hold that much weight at arms length for 1/2 hour or more you probably don't need a handgun, you can just drive your opponent into the ground by pushing on the top of his head. Keeping it simple that thing looks massive and I strongly suspect that it actually is massive.
As for 7 shots on an N frame, not possible in a 45 caliber. When you are pushing the limits of what is possible, a difference of 0.020 inch in diameter is very significant. What is possible with a 44 caliber may not be possible with a 45 caliber.
Now, in an effort to make things as completely clear as possible I've attached a PDF file of an N Frame cylinder showing the bore positions of 6, 7, and 8 shot 44 caliber chambers. You will note that if you try and put 7 chambers into that cylinder the wall thikness between chambers is less than 0.016 inch. As for an 8 shot, that just is NOT possible.
I will grant that if you make the cylinder larger in diameter and increase the diameter of the chamber spacing you can get a 7 shot 44 Magnum that would be completely safe. However, this would most likely be built on the current X frame or a completely new frame. Because that larger cylinder just wouldn't fit into the N frame.