I'm currently working on a sort of "old school" D&D-like one-shot (with option to continue) for GT. Sort of a "the other end" game. With "Carob The Plunderer", "Nriftor Nimblefinger", "Blackleaf the Elf", and "Nomad" as the cast of characters, each sort of archetypal (barbarian, theif, elven magic-user/fighter, moody human guy).
The magic system is part of one that I put together not too long ago. Basically as GT, but Caster Level = Character Level, and spells do Lethal Damage.
To cast a spell you have to roll a Spellcraft check, take the damage, etc. "Magical Adept" gives you the ability to change the Lethal to Nonlethal damage and subtract your key casting stat's bonus from the damage total. MDTs (nonlethal and lethal) still apply, so a big spell and a small con might take you out. Spells only go to 4th level, and I'm keeping most of the Direct Damage out. After you cast a spell you have to make a Fort or Will save of DC 10 + (Damage) or become Winded/Fatigued/Exhausted/Unc. The "Fatigued" is the 8-hour-rest variety, so trying to cast more than 1-2 hard spells may very well leave you tired for the rest of the day. Visible effect spells require a Fortitude save (Damage Spells, creation, most Transmutation), Invisible Effect spells require a Will save (Detect Magic, say, or Identify). Improved Caster Level is out, but Master the Eldritch Flow works as usual.
Finally, I monkied with the "spell levels". Since the level of the spell really isn't connected to the level of the PC, just the damage and difficulty to cast, I pretty much tailored the spells as I saw fit. Healing is brought down to "Healing Touch", a 2nd level spell that converts 1d8+1/2 Level damage into Nonlethal damage OR cures 1d8+ 1/2 Level nonlethal. There's also "Restful Repose" which doubles healing rates during the night's sleep (but it's damage and save isn't applied to the caster until the next morning). I so far have ruled out Magic Missile but may put in something like: "Energy Bolt" that'll do a preset amount of damage in a small area with a reflex save. The main thing, I think, to striking a real balance is not giving the wizard something he can do quite often that shows up the other characters. No 1st level "Find Secret Doors" spell, no 1st level "Deals as much damage as the barbarian" spell. I'm giving one caster Hold Portal, for instance, but not "Knock".
For spells 5th level and beyond in power, I'm using Incantations from Urban Arcana.
I have to say, I think my favorite Direct Damage spell of all time was "Red Sign of Shudde'Mel" from CoC. I'd reworked the CoC magic system to do around x2 Sanity in Nonlethal damage per spell, and left the ability damage. The caster character HAD Red Sign whenever he needed it. But he refused to use it unless the situation was horribly dire. Each time he DID use it, it was pretty spectacular, but it seldom ended the combat DIRECTLY and usually left him with something like 2 STR left. So it became a situation of "stay out of the way and hold Red Sign on as many horrible baddies as possible ... then drag my useless husk out of harm's way". Hard to make that a D&D flavored spell, though.
I'm giving Nomad a small Spellcraft skill, cross-class, and 3 cantrips with no Magical Adept (he's a 4 Strong). Read Magic, Light, and Detect Magic. To cast each he has to make a DC 11 Spellcraft check, takes 1d3 points of damage and for RM or DM a Will Save, for Light a Fort Save DC 11-13 or is Winded.
Blackleaf, on the other hand, has Dedicated Magical Adept, a small list of Druid/Ranger spells, and, say, casts Healing Touch taking 2d6 - (Wis. Mod.) Nonlethal Damage and makes a Fort. save DC 10 + (Damage) or becomes Winded.
There's "Heram the Skald" I'm working on now who is a Smart1/Charismatic3 with Charismatic Magical Adept ... I've given him a very large spell list with such useful spells as Doom and Scrying but the larger damage (wild adept) and his low multiclass saves will keep him from casting many spells in a day.
I think this will keep the casters in-line with the other characters ... hitting them twice per spell will limit their utility in a single day, but nonlethal and exhaustion comes back with rest, so each day they'll be able to step back up to bat (instead of taking weeks, as per the usual rules).
GT Strong single-class characters can rip up with a double weapon TWF. Melee Smash applies equally to each end of, say, a quarterstaff and Weapon Specialization does as well. So a 5th level Strong PC with a quarterstaff already does +4 damage with each end of his stick (MS1, MS2, Spec). TWF is, ordinarily, never really worth it. But with three levels of Melee Smash and Specialization on a double weapon or two short swords, it's quite powerful.
To bring him in line with the other characters, I let Nriftor Nimblefinger take Sneak Attack as a pure Advanced Talent for fast, with no need for Exploit Weakness. He has no Martial Weapons, so he too Dual Weilds but he does it with two Daggers. As it is, for a 1shot with 4th level PCs, 1d6 Sneak Attack isn't horrible. If I did a long-term game, I'd probably cap out Sneak Attack at 4d6 dice as that + weapon and STR damage will average out forcing a MDT on most all human opponents.
I think it'll be a fun game. They'll be a morally-challenged group of temple raiders and sometime incidental do-gooders going up against evil cultists who have a dungeon complex. I'll call it "Fane of the " something-or-other, when I get around to deciding what the evil plot should be. Maybe "The Somethingorother's Fane" ... or Temple ... or Church Of ... you know the routine.
--fje
