I can't say I have an idea at this point but I can post the links to websites I have bookmarked that list tomato problems. That way you can compare the symptoms yourself, and they may even help you narrow things down for other problems in the future. You should bookmark them for future reference as well. I just created a bookmarks folder called "tomatoes", and placed them all there (except for the last one, that's an article I copied to a text document that might be of some interest).
Tomato Problem Solver | Aggie Horticulture
Tomato Plant Problems FAQ by Kay Klier
Tomato Plant Nutrition
Color Photos of Mineral Deficiencies in Tomato Plants
Emerging Virus Diseases of Greenhouse Vegetable Crops
Tomato leaf symptoms Diagnostic Key (This section is on leaf problems, you can click on fruit, wilt and general plant decline, or crown links in the plant image at the top of the page for symptoms in those areas as well)
Greenhouse Tomato, Commercial Vegetable Production Guides, North Willamette Research and Extension Center (NON-PATHOGENIC FRUIT DISORDERS section is about two thirds the way down the page)
What's Wrong with My Tomato Plants
Commericial and Home Tomato Production in North Carolina (long list of tomato plant resources)
Blossom-End Rot of Tomato, Pepper, and Eggplant, HYG-3117-96
Weird Plant Happenings