If you think your project is going to need more than the 64K of code & 64K of XDATA directly-accessible by the 8052, I think you should seriously consider whether it is the right chip for the job.
I second that with one exception: A regular sized '51 project with occsional access of a large data storage.
I am currently developing a project with 2 Mbyte of data flash from which a bit of data is read about once every half hour. The whole thing will hum happily along with about 48k of code and, about 8k of "regular" RAM.

Erik