My thoughts: If the client wants this done, I would do it. Sure, there are a lot of reasons one could come up with to not be on MySpace, but if he wants a presence there, then why not? As time goes on he will come to understand where his marketing efforts
should be targeted.
Definitely get him going with LinkedIn and any other social media that would help his business that he's not currently using.
Just my wee lil 2 cents.
My youngest son is on MS, but he owns a tattoo shop, so I hear what Janine is saying about musicians and entertainment industries - I'd add artists to that list.