Once upon a time, I had a .REG file which would write the size and position entries into the registry for the position of Internet Explorer. I don't have it anymore, but I do recall that it was the BAGMRU thing mentioned earlier in this thread.

If you googled for documentation on those registry entries (as opposed to the search you already did), then you can set it to whatever size and position you want.

If you put the .REG file into your startup group (well, a batch file that calls it with regedit /s anyway) then you can be assured it'll be that way every time you log in.