HW Video Rotate for Msx1

No.

It is possible but it takes simply too much effort to be done. The VDP itself cannot be made to do something like that so an extra circuit is required that does the rotation. First, someone has to design the circuit and wire it to the video output of the VDP next the circuit needs to be optimized to fit inside the MSX and not use too much power to bog the whole PSU down. Then people need to get interested in this modification and take time and effort to solder the print in and install the switch which is something not likely to happen. Finally, software developers need to take interest into the modification to actually start designing software for this special mod.

All these things are very unlikely to happen unless someone is willing to do all the steps by himself and prove the awesomeness of the modification pulling other people into the mass effort of doing this.

I don't think all of this is ever going to happen.

What is the problem to physically rotate the display?

There is a Doom port for Atari 2600 (!!!) that works with the TV phisically rotated 90º. As the machine works with lines and raycasting engines are column-based, it's a very clever approach.

I meant something that could swap axes via hardware. Not the physical rotation of the screen