running code from RAM on PIC

did anyone tried to run somehow code from RAM on PIC?
i made it with motorola HC08 micrcontrollers - that have Von Neumann's architecture making easy to jump from code space to data space with loaded program, but PIC are Harward architecture based with separate data and code spaces.
my idea is to load a little piece of code from outside to RAM and let it run, then to return to original code in flash.
i don't need very fast running code and big amount of memory space.

one way to do this is to use ROMless PIC, but i don't want to use them.
other possibility is to write the code in free space in flash, with 18F devices it is easy, but the program flash memory (as well as other flash memories) have limited numbers of write cycles, so it is not acceptable for me.

is there any other solution i didn't mention?

I am afraid there is no other option, so the only option you have is to use microcontrollers which architecture supports this requirement, that is, you can execute code from external RAM or ROM.
Regards,
IanP

I think the only PIC family that offer that is PIC18F8720 and PIC18F8722 family. However you have to connect an external RAM to the bus instead of the internal RAM.

IanP, hill: thank you, I was also thinking it's not opssible due to it's archtecture, but I realise I don't know everything, so I asked to somebody more experienced