Hi Rauf,
I work with the Hitachi H8S2357F but i have seen in the news a new device 2633 with a lot of RAM.
I worked every day with 8052 and ADuC812 and PIC16C773,73,774.....
But for bigger systems is a bigger CPU with more Hardware features required.
My biggest problem is the RAM for my calculation (8052 = 256 bytes !)
(I programm the Hitachi in Assembler)

Winbond W77E468 is also right to do a bigger job.