1. Nouns for Cumbersome include Cumbersomeness, cumbrousness and cumbrousnesses

2. There are many synonyms of Bulkiness which include Danger, Hazardousness, Inconvenience, Peril, Risk, Troublesomeness, Uncomfortableness, Unhandiness, Unwieldiness, Perilousness, Cumbersomeness, Chanciness, etc.