I finally got to level 50 last night when completing the Monkey King questline. 40 to 50 went a lot faster that 20 to 30, or at least it felt as though it did. Maybe I'm just better at the game now than I was!
Now, I'll try and go back to finish all of the side quests I skipped and get all of my companions up to at least lvl 48. Also, I'll be taking my 5th character through the Presidio, and will have my guide for lvls 5-8 very soon, followed by 8-10. After that, we'll see how much further I can go with leveling 4 characters concurrently!
Lastly, I bought my very first crown companion last night: the Inoshishi Necromancer. My lineup was pitifully short of Witchdoctors (only Oldscratch) and he was less than 3,000 crowns. I may also buy Doctor Noh since, again, short on Witchdoctors and I like the look of him. Also, he has some sweet abilities . . . I just sold myself on him. I'll buy him tonight!