I've tried this:
CBCellStringInlineEditor *usernameEditor = [CBCellStringInlineEditor cellWithTitle:NSLocalizedString(@"Display name", nil)
valuePath:@"username"];
usernameEditor.keyboardType = UIKeyboardTypeAlphabet;
and this:
CBCellStringInlineEditor *emailEditor = [CBCellStringInlineEditor cellWithTitle:NSLocalizedString(@"Email", nil)
valuePath:@"email"
editor:[CBEditorStringInline editorWithKeyboardType:UIKeyboardTypeEmailAddress]];
but I always get the default keyboard.