...i see a thread just started with basically the same question so I'll keep an eye on those responses.
I may have seen the 49-1000 in a RadioShack store, but never paid it any attention until I read the bit about 32 Zones in
pcbugdoc's thread.
Although I've had a DS7000 for over a decade (does anyone remember what model number the 'siren-sized' beige RS unit without the phone dialer was before that? I had that too!) and bought a second complete kit for spare parts when my original's keyboard died, I read the 49-1000's Owner's Manual last night and it piqued my interest - maybe not for $99, but when it goes on *SALE*...
I also just read the archived messages here on "49-1000". According to
Brian H, all of the X-10 "Security Stuff", except the sirens, work with it (replacing all my door/window and motion sensors, keychains, security palmpads would be a deal-breaker! $$$).