I have a mikawa yatsubusa in a terra cotta pot. The pot is more wide than it is deep. The pot has survived 2 winters here in Virginia now without cracking. Mikawa yatsubusa is a great container plant, imo. Check a local garden center for one.

As for shishigashira, I have seen rather large versions of them, so I'm not sure how happy it will be in a pot. In theory most should work well in containers, but it is much easier to use slow growers.

Warren

Zone 7 should not require extraordinary winter protection for Japanese (please, not jap.) maples grown in containers. In excessively cold weather, you may want to group any containerized maples together or wrap small pots (not the trees) with bubble wrap, but otherwise, they should be fine.

Terra cotta, unless it is high-fired Italian ware, absorbs moisture and will easily crack or spall during cold weather. The water molecules freeze, then expand and crack the clay. If you don't care for plastic - and there are some stunning plastic resin containers available these days - then opt for wood or frost-proof glazed ceramic.

Virtually any Japanese maple can be grown in a container, provided it is sized according to the specific tree. If you want to stay small, look for any of the many dwarf forms. Mikawa yatsubusa is an excellent little container subject, but with the exception of my Sango Kaku, all my maples are grown in containers - some 25 different cultivars.