I use the "Schematic" given by keil c51 to develop my 8051 programs.
The way keil has organised the loader program just switch the output, and let it upload to the board, voila working program on an 8051. It makes for very simple and quick development of 8051 programs.
I dont have schematics, but they are quite straightforward and the keil mon51 documentation has some information. Too bad the chapter "Hardware with bootlogic" had the description "Schematic will be added later". So i had to figure out some things myself (like using HCT instead of F logic).
If you are interested in it i can make an schematic.

http://home.wanadoo.nl/b.bilos/8051_board2.htm