I asked the same question to the Mesa Boogie UK importer last month and I was shocked by his response. This is a direct quote from his email response:
These are the full retails
CB2.M2-W8W Maple £1350.00
CB2.M2-W2W Bubinga £1150.00
CB2.M2-BB Black tolex £360.00.
To give you an example of custom costs, a MKIV head in triple AAA flame maple with wicker is £2870.00
I know its expensive but they are beautiful.
I hope you can get them cheaper in the US. I did have the address of a guy in California (Dr. Hardwood - I think) that makes replacement heads, combos, open backs and thiele cabs for the mark series, it may be worth going the this route.
Ian