Twelve years later...
RS8000 remote on the cheap (not full function, but basics)
I picked up a used Marantz RS8000/U1B receiver on ebay with no remote. My goal was to access the OSD menus which you can't through the bottons on the front panel. You'll need a composite or S-Video monitor to see the OSD screens (sorry, no HDMI or component output on this monster).

Tried a GE 8 unit controller... no go with the codes. Then I remembered that I had an old (6-8 years old?) DirecTV RC65RX remote... why not try it.

Directv has a list of codes online for the remote for AV equipment and the remote has a switch to control 4 different things (Directv box, AV1, AV2, TV) at the top. I looked up the Marantz, and there were codes! I chose AV1 and started trying the remote codes. To set the code, hold mute and select until the display blinks twice. Enter 5 digit code 31289 (make sure the LED blinks once for each number entered), and it should blink twice after the fifth digit).

What works: Power (PWR) for on/off, Volume up, down, mute, numeric keys (each take you to a setup screen for an source (select analog, digital input....). The MENU key doesn't take you to the OSD menus, but after hitting a number key (7 for example), you can use the up arrow and you're at the MAIN MENU. Now the arrow and select keys work, which is all you need. I was able to configure the speaker and subwoofer setup and choose which input (digital or analog) I wanted for each source.

Saved me big bucks instead of buying an old remote just to setup and control the volume and power. Thanks DirecTV!