Client upload

I’m going to be running a screen printing business and our site is going to run using wordpress. I was wondering if there’s a plugin out there that will allow a client to upload their artwork to us, with no filesize limit. They don’t have to register, I could register them on my end because this would be done after an initial contact is made.

What is the best way to do this? I just want to make sure they can’t post anything, or change any settings.

Thanks,
Matt