10 seconds is ok, it's not long enough to warrant a SD or MMC card and MP3 codec and a good size you can do with a micro and a eeprom.
If you work with microcontrollers and don't mind building and programming a complex device there is some stuff here that you can use to record/encode/playback sound;
(algorithms to encode 8bit sound to 1bit)
Roman Black's BTc 1bit Sound Encoding Algorithms
(Windows software to help, playback hardware)
BTc Sound Encoder v3.0 - free sound software