No, I don't think it would be a good idea to add extra steps for ignoring members, and there are no buttons available on member profiles.
Bitcointalk is not perfect when used with mobile devices, some would even say it's bad, but maybe someone could make a simple script to optionally hide or move ignore button and other elements.
New mobile responsive theme would probably fix this and many other issues, but don't count on it to be released any time soon.