I'm tempted to host a DOS/PC challenge, but I might have to get approval, and it might not be too popular. Here's some games I'd have:
For Doom series (except Doom 3), Heretic, Hexen, Hexen Deathkings, and Strife, I'd allow the use of ZDoom, vanilla Doom, Doom95, Doom Legacy, Chocolate Doom, and Skulltag provided Freelook is turned off, the players can't jump or crouch, and there's no use of any weapon mods unless the challenge requires a weapon mod (i.e. Drown in Blood maps rely on eweps.wad due to the massive amount of monsters the maps throw at the player and how insanely difficult it would be with regular weapons). I might be more sympathetic on TNT Evilution and allow cheating to some degree because the first map only supplies a Plasma gun, a shotgun, and a chaingun, and in the path of a switch that is needed to get the blue keycard, three Cyberdemons await splattering the hapless Marine with their rockets, and a mancubus is RIGHT AT THE BEGINNING OF THE LEVEL. I would let the players either godmode past the Cyberdemons or MDK them before proceeding to the switch. I may allow jumping and crouching in wads that need it, like Jumpmaze and Doom Barracks Zone.