nsi memory leaks fixed yet?

I think that may not be a bad idea. One thing you might want to consider is a fresh install of Windows. As much of a pain as it can be, this might be the only way to ensure that this goes away 100%. 

One thing I forgot to mention when I first posted this potential solution, was that after experimenting with installing\uninstalling versions of IE and observing if the leak returned, eventually I performed a fresh install of Windows and left it running IE9.

It has been well over a month, and my system is still running fine. The SVCHOST process is running at 13,540K and stays in and around that number. For what it is worth, this system is used to monitor my entire network (1,000's of nodes), so you can only imagine the amount of network traffic that it generates.

I you haven't already, I would probably give up on trying to run a current IE version, and just start using Chrome or FF- both of which IMO are much better.

Great, thank you.

On side note, since Microsoft closed this thread and won't reopen it, would it do some good to start a new thread, and then link this one to that one?  Just a thought.

The thread isn't closed. A support engineer marked his colleague's reply as the answer, but it's clear both from the OP's responses and the rest of the thread that those generic remedies don't solve this particular problem. I've now unmarked the answer.A thread can only really be closed by locking to prevent further posts. I can't see that that would help in this case 

My issue had gone away when I plugged my ethernet into a different router.  So I believe the problem is somewhat hardware related.  Then I built a new computer and plugged it into the original router (the one with the problem).  All seems stable after 2 months of running (knock on wood).  The computer with the problem was running Windows 7 as an upgrade from Vista.  The new computer is Windows 8 from a clean install.  I brought the old computer to my parents, but they don't leave the machine on 24/7 and so would not realize if the problem persist.

On side note, since Microsoft closed this thread and won't reopen it, would it do some good to start a new thread, and then link this one to that one?  Just a thought.

Right now I am trying with Auto Update disabled for Microsoft Update. See how that goes for the next 15 days or so, then I will be trying a FRESH install of Windows 7, be on an entire new PC build as well. The new PC is going to be an Intel i5 on a gaming board, with completely different RAM. Be posting those results by the end of the month.