What you want can be done; however I would consider it wrestling a microprocessor into becoming a PC. Just for reference have a look at the Philips P89C51Rx2 and the loading. While this is not supposed to be "program replacement" but rather "program update" it will take 10.000+ loads. If you look at pp 46 of the data sheet, you will see the method of obtaining the functionality of what you want. Using that as a model, you should be able to transfer the method to your processor. Another thought, is your approach (loading from eprom to ram) the right one? An In-Circuit-Emulator loads from the PC to ram and run the program there, have you considered a small bootloader in eprom and loading the program from the PC to the RAM.

Erik