Well, we probably aren't sure what is being asked exactly. Technically, all the Falcon kits out there are scaled with their ramps based on features found on the studio models (mainly so the details blend in properly when the ramp is closed). As such, an open ramp tends to be secondary.
If you are looking for a ramp like the set piece, I don't believe ANY modeler (with the possible exception of a Japanese modeler or two) has done one since all the "full size" Falcon sets that have been constructed for SW are undersized relative to what they should be in the first place (and minor detail features on the rest of the set piece tend to be different as well). As such, many modelers whom I have seen do Falcon model based dioramas with the ramp open just leave it as is and consider the studio model style features to be more accurate than the set pieces.
As such, you are kind of on your own in regards to ramp modifications. Plus, when done you aren't going to see all that much of the ramp anyway as it is somewhat hidden and shaded when on display (unless lights are placed down there). As such, anyone who is going to look at the ramp has to bend down to its level. As for a creative way to hide any flaws at the top of the ramp, just put a figure or two on it to act as a sight blocker and the eyes will be attracted to the figure, not the ramp.
You can spend a crapload of time on the ramp, but it is a minor thing relative to the rest of the mods needed to bring an MPC Falcon up to snuff.
