Level 1000

Well, if you leave all other game content appart and just focus the level itself then there is hardly a limit.

Check out once the discussion on Siegecore about level 300, Volkan/Pheonix found out how to (almost) infinitely expand the char level, and he even made a mod for/until level 300 with appropriately adjusted items, magical bonuses, gold drops, etc.
So for a good level 1000 mod i guess you had to do the same work, but while for level 100 or 300 most (exponential) game formulas still may work, for level 1000 or higher they surely begin to produce absurd values - if the game internally is able at all to handle the large numbers correctly these formulas are going to produce.

Indeed i have played around a bit with that subject, but canceled it soon. If you want something more than a simply replaced/upscaled number in the char gui then the modding effort is quite extreme. :o

This packmule had almost no chance to eliminate these 600x under-levelled Mordens, luckily the life regeneration of packmule ticked like insane. So i left them alone and went shopping meanwhile, after 1 hours i guess it was done.

Back in ds1 there were people asking about high level mods, wanting to get to level 1000 and some people replied you could not do that, that 180 or 250 depending on who was saying. To prove a point, as I was saying there was no limit, I put out a simple mod that went to level 1,000,000. I have not worked in ds2 nearly as much as I did in ds1 but from what I could see you have the same infinite level cap. Not that a level that high would be of much point but it can be done. Looking at my files that was from back in July 2004. There are a lot of little mods and code buried in siegenetwork.com if someone wanted to spend a bunch of hours digging.