I ran Isle of Dread 3e style near the very beginning of my 3e games.
in a word... it ROCKED.
Once the party got tough enough and skilled enough to handle a charging triceratops...
I hit them with a Triceratops advanced to Colossal size. 36 Hit Die Triceratops....
Triceratops: CR 7; Gargantuan Beast ; HD 36d10+324; hp 522; Init -1; Spd 30ft; AC 22; ATK Gore +32 melee; DAM Gore 4d6+13; SA Charge for double damage, trample; SQ Scent; SV - Fort +21, Ref +11, Wil +13; Str 28, Dex 9, Con 29, Int 1, Wis 12, Cha 7
When I pulled that sucker out, my daughter ran upstairs and came back down with a toy triceratops that was EXACTLY the right size on our battlemat...
The party was smart enough to run for their lives.