I have been thinking about how to add more resources to the uzebox, and I thought of a simple board that could go on the ext port by sharing the SPI buss with a different chip select pin, a microchip AT23LC1024 (128K spi sram) should work.
The resources could be loaded off the sd card and then flash and start the main program, this has the following advantages over the sd card alone:
1. access to resources is faster than the sd card
2. the sram driver is simpler and uses less program space
I'm going to order a few from mouser and try it.
http://www.mouser.com/ProductDetail/Mic ... 23Aiprk%3d
sram
Re: sram
Yes, SPI ram is a quick and easy way to add more memory. It's been discussed a couple time in this forum, but nobody has tried it so far. Was on my wish list though 
... Let us know how it works out. I recommend you use PA6 or PA7 as chip select.
... Let us know how it works out. I recommend you use PA6 or PA7 as chip select.Re: sram
I have some pdip spi memory laying around that I have been meaning to try. Atmel made some examples of using spi memory as heap. I would have find it again. The big catch is that they add 1KB to the compile. 1 KB would take away some from the game. It may be a good opportunity to pull some stuff from the SD and place it on the RAM.
Re: sram
For only 1kb that is a huge gain you would get, being able to leverage SD with all that ram. Would take some complex work, but I'd love to get a peek at what kind of possibilities that opens up.