Why not add a USB controller (controller IC plus socket available for not more than $4 and maybe 1 square inch of board space)? USB host mode gives you a lot of flexibility to add any device you can find or write a driver for in the future.
You can get cheap LCD displays on eBay for around $4 for a 16x2 model. Of course you'll need some headers to mount it, but that shouldn't add more than another $2 or $3 to the price tag.
Same thing goes for an SD card socket (or microSD if you want to reduce the board space required). Around $3 is all it costs for the socket and you don't need any other support chips that you don't already have for other circuitry.
What other peripherals? Oh, an ethernet port. Microchip makes some suitable controller chips for about $4 (SPI interface). Add a socket for under $2.
The board, as advertised, already has USB and Ethernet functionality and connectivity with the firmware.
Yes, perhaps an expansion card with LCD capability could be arranged, no they are not that expensive. Perhaps I will add a communications port for peripherals that can be purchased seperately on these counts (LCD, SD, etc.) without having to include them in the project and make the whole thing more expensive. I will not, however, impose features on people. It will be barebones, then will have the capability to expand with whatever fancy parts you'd like to have.