Funny you should ask since I just finished doing a quick search and running it a few times
Here's the sitehttp://www.fantasysportshelmets.com/random.php
You will have to sign up for free, maybe futz with it a bit before it lets you in, go to managers page and enter the league info, then run generator as much as you like.
OR - do what I did when I had no generator.
draw #'s from a hat! Assign each of your 10/12 teams, 5 entries for each - keep pulling until the fifth of one team's number comes out. That team gets #1 pick, and so on. Works exactly the same.