Where can I find a mod that removes the new Reaver zombie introduced in Brotherhood of Steel? Aside from this one enemy, the game is very playable with high level characters.

I've not heard of a mod that does this, but if you open up Broken Steel in the GECK you could probably just delete the Reaver from the Feral Ghoul spawn list.

The Spawn list is called EncFeralGhoul and the Reaver is called DLC03CrFeralGhoul4A

What is the latest version of GECK? http://geck.gamesas.com/index.php/Main_Page mentions version 1.5 in the "The Garden of Eden Creation Kit" section but on the "Index" it only lists "What's new in v1.1". Due to this inconsistency, is there a version newer then v1.5 that simply isn't mentioned on that page?

That does sound confusing. Maybe they didn't think there was enough new stuff to make another "Whats New" article?

1.5 should be fine, I just checked and I'm still on version 1.1.. <_<

Will I need to do anything with the Broken Steel.esp file included with the unofficial fallout 3 patch too? Also when opening Broken Steel in v1.5 of GECK I get
Is this normal? Do I click Yes, No or Yes to all?

Edit: I also can't find "EncFeralGhoul" anywhere in the program after opening BrokenSteel.esm but can find DLC03CrFeralGhoul4A. Where is the Spawn list?

Right click on DLC03CrFeralGhoul4A and select Use Info. From there you can select EncFeralGhoul. Make sure you have both Fallout 3 and Broken Steel loaded up in the GECK. Also be sure to save your mod and then activate it, that's not meant as a slight I have spent more time than I care to admit looking at my mod and trying to figure out why it wont work inly to discover that I never actually checked the box to activate the mod.

Okay so going against your suggested process of performing the deletion of the enemy. I selected Fallout3.esm, BrokenSteel.esm and "Unofficial Fallout 3 Patch - Broken Steel.esp" with "Unofficial Fallout 3 Patch - Broken Steel.esp" being "set as active file". I deleted the creature from the spawn list and saved the file. I assume it saved the change to the unofficial patch plugin rendering no need for me to create another fresh plugin just for this change?

Good lord man, just type the frigging console command to get the ghoul mask and call it a day, hell, get a few extra masks for your followers too! :rofl:

>.> I got the mask now the legit way! And I still like killing ghouls, it's just the Reaver one is soso sooooooooo over powered it's just not funny.

now wasn't that easier lol...

Correct, the changes will be saved to the Active File. If you don't make a file active then the changes will create a new esp file.

With that done go check out some high level sewers and see if you run into any Reavers.