They still allow them, you just have to sign up for one of their pre-made sites or whatever they are if the option for an HTML-Only site isn't available when you register (I just checked and it popped up for me).
Anyways, sign up for their pre-made stuff, pick whichever theme because it's not going to matter. When you've signed up, go to 'Control Panel' at the top of the page, then click on 'Website Settings' when you get there (it's under the 'Manage Website' section). Scroll down to the 'More Settings' section on the sidebar and select 'Downgrade Account to HTML'.