3DShell does both FTP and archive extraction.I would test retroarch nightlies more frequently if I could a) avoid taking the SD card out, b) avoid the lengthy process of FTPing (or whatever) thousands of files, which brings the 3DS to its knees, and apparently nothing can be done about it except for using FTPd on the device and setting the client on the PC to 1 file simultaneous transfer only).
It would be easier if we had an unzipping homebrew tool on the 3DS, but it doesn't seem to exist. Am I wrong?