Rycanada, I just remembered...
Another example to look at would be Spycraft 2.0's NPC creation system. It's a set of charts, one for each statistic -- initiative, attack, defense, resilience (all saves lumped together), damage save/vitality (hitpoints), competence (all skills lumped together), and so on -- one side of the chart has the "Grade" of the statistic and the other axis has the "Threat Level" (a CR analogue).
To create an NPC, you choose the Grade of each statistic, based on how good the NPC should be at each. Increasing a Grade increases the XP award of "defeating" the NPC by a certain amount. Then, you can choose special abilities to add, each of which also add a certain amount of XP award.
When the PCs encounter the creature, you cross reference it's abilities with whatever Threat Level (CR) you deem appropriate and you've got the stats you need.
To take an example from the Spycraft 2.0 rulebook, a zombie might look like:
Zombie (Standard NPC - 36 XP): Init II; Atk V; Def II; Resilience IV; Damage Save VII; Competence I; Qualities:
all thumbs, clumsy, construct, damage reduction 5.
Against a 1st level party, it'd look like:
Zombie (Standard NPC - 36 XP): Init +0; Atk +0; Def 10; Resilience +1; Damage Save +9; Competence +0; Qualities:
all thumbs, clumsy, construct, damage reduction 5.
Againt a 10th level party, it'd look like:
Zombie (Standard NPC - 36 XP): Init +1; Atk +7; Def 13; Resilience +4; Damage Save +12; Competence +0; Qualities:
all thumbs, clumsy, construct, damage reduction 5.
And each player in the party would get (character level x 36) experience points for defeating one zombie... 36 XP each for the first level PCs, or 360 XP each for the tenth level PCs.
There's also a project to convert this NPC creation method to be compatible with D20 Modern and D&D...
http://www.enworld.org/showthread.php?t=164910 ...Looks like Adamant Entertainment like be releasing it within a month or so.