tell application "iTunes"
set theTracks to selection
if theTracks is not {} then
display dialog ¬
"Add this much to each track number:" default answer ¬
0 buttons ("Do it now!") default button 1
set theNum to (the text returned of the result as integer)
repeat with i from 1 to count of theTracks
set theTrack to item i of theTracks
set the track number of theTrack to ¬
(the (track number of theTrack) + theNum)
end repeat
else
display dialog "You need to select some tracks first."
end if
end tell
Now that the track numbers are all in order (notice we intentionally ignored track count), select all the discs and set their album name and track count to the obvious values. Now your tracks are all combined neatly in a single album, as they should be. Ah, so much cleaner!
Note: you can also fool with disc number, if you wish to preserve that information in some form. I choose to ignore it, but it would not be hard to add this to the script. I'm guessing it wouldn't be that hard to automate the entire process, in fact.

