Steven Martin wrote:

>Does crossover do more harm then good?

Only if the overcrosser stinks at the overcrossed.  Some great success
stories:

Eileen Farrell
Jean-Yves Thibaudet (Those jazz albums rock!)
Andre Previn
Wynton Marsalis
Friedrich Gulda
Jacques Lousier
Menuhin with Grapelli

Some dismal failures:

Kiri te Kanawa's numerous failed imitations of oh, say, Jo Stafford and Julie
   London
Sylvia McNair
Jessye Norman
Placido Domingo meets John Denver
The Three Tenors' god-awful attempts to sing broadway.
Andrea Bocelli

the list goes on.

My point is that if a musician has the chops to deliver *convincing*
renditions, that are stylistically correct, then by all means go for it.
If not, play in your own neighborhood.

I do have to admit one secret sin though.  I have always loved Streisand's
classical record.  I think that the reason that I like it so is that she
sings the songs like Streisand and not like she was trying to be Sills.
I have always admired that.

Kevin Sutton