As I have heard it, the problem with the lag caused by the Last Active feature, was that it constantly had to calculate the information retrieved from every single account, including all the ghost accounts... Somehow that ate too much of the server capacity.
That's the reason as I understand it. Maybe they'll work around it eventually.
dan mcneely should get in contact with tom from myspace, hes got myspace scripted *almost* perfectly. shpigford could use some pointers from the myspace crew, dontcha think?