Before UHD came it would be easy to make a home cinema entirely by B&O products with the exemption of the screen. What I mean is you could get a Beovision/Beosystem preferably one that has 7.1 decoding capabilities (if Beovision is what you would go for). Connect to it a matrix and on the matrix a sony projector. As far as sound is concerned fronts I would go for beolab 9, rears beolab 3, sub beolab 2, surround beolab 3. As center I would use the beovision's speaker or in case I had a beosystem I would get a beolab 10. I think the setup would definitely cost less than 100k.
Now for the UHD version of it I wouldn't buy a beovision. The reason is that they are very expensive and for the last couple of years they tend to change very quickly so I don't want to end up with another black box. So I would definitely buy a beosystem that has 7.1 and UHD. For example it could be a cheap version of a beosystem with 5.1 and UHD without any integrated speaker and a 7.1 and UHD with integrated speaker as a more expensive alternative. DO YOU HEAR ME B&O??????
But there is no Beosystem, so I would go for an AV Amp preferably a Yamaha. As far as the speakers and the projector are concerned I would go for the same ones I picked for the B&O setup. Given that the Yamaha supports Atmos I would go for a couple of Beovox 2-2 or palatial for ceiling installation.
Last but my no means least. I think that a home cinema needs a projector. Even a TV with 130" diagonal doesn't bring the atmosphere a projector has. In other words the projector is kind of the record player of the home cinema. It is bulky, heavy, you have to wait (at least a bit) for it to start, you need to have the drapes closed to watch.....but it adds character...