Wow, didn't realize I get asked for hacks
Just brainstorming out loud here:
If you wanted to do an online.cgi style thing, I think you'd need to add a profile field like "lastpage" that would give the URL for the last visited page (if you wanted to do it that way)
Or you could just do a simple version that would translate the last visited time to a readable version and display it on its own page... Pretty simple actually.
My next hack maybe?