Yeah, I'm gonna do it!
If you want to join the osr Challenge: A September of Short Adventures, be sure to sign up! Times a wastin'!
And if you're interested in using a Balrog, too, here are the stats I came up with:
Balrog; No. Encountered: 1; Alignment: Chaotic; Armor Class: 2; Hit Dice: 10d8, Hit Points: 56; Attacks: +1 sword (1d8+4) and +1 whip (1d6+4 + special); Save: F10; morale: 12; Special abilities: flight, 90 feet darkvision, Strength 18, immune to non-magical weapons but silver weapons do half-damage, immune to sleep, charm and hold spells, drag attack (if the whip attack is successful, the Balrog drags the target against its flaming body, inflicting an additional 3d6 damage).