Wacom graphire tablets are great, that's what I have. If you can afford larger one, they help, only the very rich/professional need the Intous line though!! ;) IIRC One I got is 6"x8", really cool. Latest version is a "bluetooth" wireless so you can have it in your lap if wish.

They also have a range of EXTREMELy expensive "tablet monitors" you can draw on the screen as per a tablet, wow!

The figure desginer or DAZ studio (with free models form DAZ, like Vicky, Mike etc) can certainly do what you need.
I know Poser can do "cartoon" renders, that is LINE art, which maybe helpful too? But that's more money and you probably don't need.

I think there's a plugin for DAZ studio that does line art?

this is a quick pic done in line art from Poser.
Hope this helps :)

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