High Crit Vorpal Fullblade? With RRoT? And a . . .3[w] Endounter power? 9x12=108, add some static bonuses (leader bonuses to damage, etc), and it is doable.
Jay
Vorpal is an epic-level enchant so unless the DM is handing out +5 swords to mid-paragon characters...
I can't speak for his avenger crit, but I can give you a breakdown of our rogue's crit damage (with Sly-Flourish, his primary at-will). The avenger probably has something similar, but he's probably using an Executioner's Axe (so replace all [W] d4s with d12s):
4(1[W])+6(Dex)+4(Cha)+3(Enh)+2(Weapon Focus)+28(Sneak Attack)+3d12(Vicious Dagger)+1d12(War Ring)+1d10(Devestating Critical)+1d10(Flame Bracers)+2d4(High Crit weapon):
So, 4d12+2d10+2d4+47. Average damage around 90, though I don't think he's ever rolled less than 90 unless he (for some reason) didn't have CA for the attack. If he's hit a milestone, he can use his war-ring's daily to make the crit maxed at 121 damage; if not he can just add +2d12 to the crit.
He's aiming for a few magic items and feats to increase his crit damage:
+4 Bloodiron dagger(d12s go to d10s, but repeat ALL bonus crit damage next turn, add +1 to static damage).
Paragon Executioner's bracers(replace Flame Bracers 1d10 fire with 2d6 untyped).
Some type of Citrine.
I've told him to get TWF and TWO so he gets the +1 damage and an extra off-hand attack when he crits. He'll probably go that route if he doesn't multiclass bard to get a Lilting Songblade...
Also, if my Ranger gets the Bracers of Ice on his loot list, the rogue gets my Gauntlets of Destruction(reroll all 1 on melee weapon damage). Decent for his regular d4s, even more useful for that big handful of crit dice.
As a fun side note, he keeps all his crit dice in their own separate plastic dice container so when he gets a crit he pops the top off the container and vigorously plops them in the center of the table.