Hi Karem, I suggest you to use x86 based SBC because 8051/52 family has the limitation of 64Kb.Code/64Kb.Data and there´s no C++ compiler you can port to.
Give a look to: http://www.embedtec.com/

They make several x86 based SBC with ISA/PCI and other buses. Hope it´ll help. Germán.