Sonicblue cut prices on some of its digital video recorders in its ReplayTV line. The Santa Clara, Calif.-based consumer-electronics makerthe ReplayTV 4500 line in June and on Friday cut prices on the DVRs and began offering mail-in rebates for models within that line. The ReplayTV 4504 DVR with 40 hours of record time was cut from $449.99 to $349.99 with a $50 mail-in rebate. The ReplayTV 4508, which comes with 80 hours of record time, was cut from $749.99 to $449.99 after a $100 mail-in rebate. The ReplayTV 4516, with 160 hours of recording capacity, was cut from $1,249.99 to $899.99 after a $100 mail-in rebate, and the ReplayTV 4532 with 320 hours of storage room was cut to $1,749.99 to $1,299.99 after a $100 mail-in rebate.