"Does it exist a 8052 with 16-bit DAC or even wider, maby 18-bits"

Yes, Burr-Brown (TI) has one, I believe it has been released by now, sorry forgot the part number.
It is difficult enough to keep the digital noise away from a built in 8 bit DAC, I warn you that using a built in DAC of such high resolution will require you to spend agonizing days on your PCB layout.

Erik