Given the following constraints what is the maximum number of attacks in a round for 3.X edition?

A former DM has had the same recurring NPC/GMPC since I started playing in his game. This was 20+ years ago and we started in 1st edition and slowly made our way through the years and editions. We updated our characters as we went to the new editions. Now this NPC/GMPC is the most reviled in his games, any time he shows up all the players immediately want him dead. We stick to character though.

The question will be broken up to hopefully get expert answers from each of the editions in which we played in this particular question it will be specific to 3.Xe. I am skipping 4e (as we all hated it and only played one session) and 5e because I know for a fact that it is not possible there (yet).

The question is as follows:

Give the following constraints what is the maximum number of attacks in this edition:

  1. NPC is an Elf (In this edition it is irrelavent I suppose).
  2. He was a Thief-Acrobat in previous editions and I assume multiclassed, probably Fighter-Thief, due to how 3.X prestige works let’s assume just Rogue for this edition, although any official prestige class is fair game. Character focused on tumbling and thrown knife attacks.
  3. The weapon of choice was throwing knives.
  4. Assume unlimited ammunition as he had a bandalier that had the knives return.
  5. I know he could throw 3 knives at a time (pretty sure this was a thing for shuriken from Oriental Adventures).
  6. Assume all official sources and Dragon Magazine since the first issue are open.
  7. I know of this question and assume there is a variant with knives.
  8. If I recall he threw with both hands as well.
  9. Assume prestige classes are open, this DM even as a player had a tendency to stack multiclass options with min/max precision but assume Rogue is the primary focus.
  10. Assume Quick Draw.
  11. We were always between 8th and 15th level when I met this character.
  12. I do not recall spell-casting but not ruling it out entirely but main build would likely have been focused on mundane means.
  13. Assume focused magical item augmentation as well, just calling it out even though the aforementioned bandolier alluded to it, but for the most part official items other than that.
  14. Assume no flying invisible helpers as suggested by HeyICanChan or for that matter third party interventions or Aid Another.

The end result in game was quite literally at least 2 dozen attacks per round, perhaps more. Which I have questioned him multiple times about the build and legitimacy but he as refused to provide any answers. I know DMs do not have to justify but this, combined with a number of other things over the years has lead to distrust. I have since stopped playing his games altogether, so this is just a verification on whether I have overreacted.

This was broken into 3 questions for each of the editions.

AD&D, AD&D 2nd Edition, and Dungeons & Dragons 3.X.