You can buy one from instantcake for $20.
There are some members of this forum that have a library of images and would send you your image. I cannot remember the name of those users right now. Maybe someone else will chime in with that information.
Sony S2, SVR-3000, lifetime (11/02)-160GB drive upgraded 11/04 (limited to 137GB)
TiVo S2, 540 unit, lifetime (7/05)-250GB drive upgraded 5/06
TiVoHD, lifetime (10/09)-1TB drive upgraded 5/10