Frugal, your achievements since you initial posts are inspiring! Great job!
Only one caution.... now that you are in the position to get new credit, be careful New credit, introductory low APRs and BT rates, etc/ require a careful balancing of financial planning against FICO planning. You are now at that plateuau, so consider the pros and cons of each.
Securing new credit or low BTs against existing credit can be a financial gain in reducng interst, if done wiselly. BTs are something I would look closely at. They hit you with a 3% one time, up front fee, which if in the extreme you did every month, would be 36% annual rate. So you have to consider that. And if you dont pay it off in the intro period, it reverts to your regular card APR.
As for FICO, as opposed to financial, effects, new accounts, if you apply, will cost you a hard inq So will many CLIs. They may also lower your avg age of credit. Also, if you get a new card with a low CL, then minimal charges against it can easily shoot your %util on that card up to high leverls.
If you are stable with your current credit, have it under control, and are seeing FICO increases, think long and hard before you get the golden feeling of improved credit rating, and start appiing for new credit that is optional, and not necessary................