I needed a giant octopus for an underwater encounter, and a Grell worked just fine. Swap out Fey Step for Elven Accuracy, give the Fey Knights a Longbow ranged attack, remove the Incanter's Spear attack, and be done with it. Instead of trying to bump up the elves 6 levels, or making some from scratch, I just used the Eladrins in the MM and called them Elves.
In a current adventure I'm running, the PCs (lvl 8) are to be confronted by some elves. I've used a plethora of different creatures just by changing the names of things in the Monster Manual and slightly adjusting the effects of certain things.
