The latest version of the engine (V1.01) has cartoon models as stock media.
Upon Steam release, I can imagine there will be artists selling cartoon models in the TGC store.
You mentioned that you have been learning to model yourself. My advice is, stick at it. Modelling cartoons can actually be easier than making the more realistic models. You have complete control over how things look, if you want to completely stretch the proportions of things, it will be accepted due to the nature of the assets.
Keep practising and I guarantee, you will make something that you will be happy with.
I will be remaking all of my tutorial videos, as I need to re-brand them to match the Game Guru brand. If you like, I could add cartoon models to the list of videos?
Cheers
Jay.