There's no law that says a variable contrast head can't also be a condenser head. However, there does not appear to be such a thing commercially available as a production item. I am assuming that by "variocontrasthead/multigradehead" you mean something more sophisticated than a filter drawer.
I would venture to guess that with variable contrast heads as with color heads it is more economical to mix the different colors as diffuse light. A variable contrast head is, after all, just a color head with two colors instead of three. Mixing boxes have been the norm for years and everyone seems happy with the general design.
It's interesting to note that Glenn Evans (glennview) has made a variable contrast source for the Durst 138 enlarger from an Ilford 400 Multigrade head. The lamps and filters are arranged in a special fixture which replaces the standard lamp socket in the Durst. The filtered light projects upon a diffusion plate which is then projected by the condenser system. In that way it's essentially a condenser variable contrast head. The diffusion plate is about the same size as the Durst bulb, so it should mimic the original optical system pretty closely.
Originally Posted by naaldvoerder
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