do you think it would be a bad idea to make a red velvet cake and use cream cheese frosting for the inside and use butter cream frosting on the outside?

No sounds good. Stiffen or stabilize the cream cheese frosting with meringue powder, so the layers don't slide apart. I just did a red velvet w/cream cheese frosting for a graduation dinner today

Sounds good to me. I just add extra powdered sugar to stiffen up the cream cheese icing sufficiently.

ok you are talking about ABC for out side ?? I am not sure, I've never tried it, I think if this is the time doing it, don't do it for a customer, you may want to do a trial cake and have others taste too... good luck, let us know what you decide.

if the customer wants cream cheese icing on the red velvet (i typically only offer the cooked frosting - i don't do buttercream on red velvet) i use the crusting cream cheese icing that is in the recipe section here on CC. It taste good, and still has the stiffer consistency of buttercream, plus it crust so I can use all of my normal smoothing methods on it.

CC crusting cream cheese recipes:

http://cakecentral.com/recipes/6817/wedding-crusting-cream-cheese-frosting

http://cakecentral.com/recipes/2047/crusting-cream-cheese-icing

HTH

I've done red velvet cake several times with cream cheese icing as a filling and SMBC as the frosting. Works great!

Someone (can't remember who) on CC recommended adding a can of cream cheese icing to my butter cream on a red velvet cake. I did and it crusted well. I covered it with fondant. Turned out great. Tasted great.