Can Void Staff get the Last Whisper Treatment?

Whenever I play Karthus, I tend to get Void Staff as 4th - 5th option to deal with anyone building MR, but while I'm waiting to get that item, I'm usually just sitting on a big pile of Gold that I can't even use since even with both components built, (and usually, I only have 1 empty slot) Void Staff costs 1365 gold. Now, looking at Last whisper, it starts at 1300 gold and builds out of a long sword, and that builds into 2 other items. One deals extra damage based on how much more health they have than you (LDR), and the other applies Grievous wounds (Mortal Reminder).

Now I'm not saying we split Void Staff into 2 distinct items per se, simply because I'm currently trying to think of a different alternative to Mortal Reminder (since applying GW is a bit redundant for those who already get Morellos), whereas an LDR based VS upgrade actually sounds at least decent. At the very least, I'd like to be able to not have to sit on top of a pile of gold while I wait for Void Staff.