Quick OOTP update:
While entering the rosters that I DO HAVE (Ahem, slackers...) I noticed that OOTP doesn't apply ratings to the really old guys very well when using the Lahman db. Guys that played in the Dead Ball Era get screwed for power ratings.
So, I found a better alternative. There's this guy named Ankit that created several variations of the Lahman db and one of them is a Normalize version of it. Basically, he took the Lahman db and normalized the stats for the historical players to match up with today's game.
I took a look at a few of them and they look pretty good. For example, in 1901 Sam Crawford had 16 HR. That was a ton for that era (props to Koya). Ankit's normalized db has Crawford with 49 HR for that year. Seems pretty good to me.
Two caveats:
1) It only goes to the 2002 season. This isn't that big of a deal since we can use Lahman for 2003 or 2004 since they won't need to be normalized.
2) He's apparently working on a newer version with a different methodology for calculating the normalized stats.
I'm going to email him and see if I can get an update on the new version.