!!! Random addressing of the screen area

I am interested in the possibility of hardware implementation of the random addressing mode of the screen area. As a standard, starting from the ZX Spectrum
128K model, the screen area can be placed only in #05 and #07 pages
RAM.
In order for Everyone to better understand what is at stake, I will give
conditional examples of controlling the proposed modes.

------------------------------------------------------------[Option1]-
;conditional example of mode control
ld bc,SomePort
ld a,SomePage
out (c),a
;SomePage is an arbitrary page number in which the screen area is located from address
#c000.

How much more difficult is the implementation of the following options.
------------------------------------------------------------ [Option2]-
Writing to the high address port changes the current read address
of video memory. In this case, you must first enable
the corresponding RAM page.

;conditional example of mode control
ld bc,SomePort
ld a, ScrAdr/256; high byte of the screen area address (#40-#FF)
out (c),a

or a more radical option, but less flexible option.
------------------------------------------------------------[Option3]-
;conditional example of mode control
ld bc,SomePort
ld a,%xxxxyyyy
out (c),a
;where yyyy is the RAM page number, and xxxx - high byte of the address
of the screen area (#40-#F0).Save the price, slightly lower
free prices, from #4000 to #f000, to object #1000.

ra.id

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