In my entire life, I have NEVER done business with a place whose service after you bought the thing was more responsive than their sales was before you bought it. That's something I'd think about -- REALLY think about.
Two months is a long time to wait, I agree, but compared to how long you are likely to own the bass (and hence have a relationship with it's vender), it isn't that long. Besides, it is fairly likely that you will have to wait two months.
Tips for buying from Carvin:
1. Don't use the web site, call the toll free number.
2. Ask for Carl.
3. Ask him to tell you what you what they have in the current inventory.
Basically, they have 2 kinds of instruments in inventory: things people ordered and then cancelled BEFORE it shipped, and things they know most people want.
I bet if you called, you'd find they had a 6 ready to ship.