First, a search on Google quickly turned up two online sources for NSF-approved rubber cutting boards: apexstores.com and chefstore.com. They have a variety of sizes and prices.
Second, microwave sanitizing is not recommended because most microwave ovens have cold spots, so you can’t tell if the entire surface has been heated sufficiently to kill all bacteria. If it doesn’t get hot enough to kill them, all you’ve done is give them a warm wet place to breed. That last warning also applies to dishwashers; if it doesn’t have a “hot start” mode to preheat the water coming in from your water heater, things may not get sanitized.
Third, rinsing with anything after using a bleach solution to sanitize is not recommended. The USDA recommendation (as reprinted in the book “Home Comforts”, which while appropriately straight-dopish in most respects, suffers on this particular issue by not having online updates; that is, she comes down on the plastic-is-better side) is: “wash with hot, soapy water, rinse thoroughly with plain, clean water, immerse in solution of one teaspoon household chlorine bleach per quart of water for several minutes (or, if it can’t be immersed, flood it with the solution for a few minutes), then air dry or pat dry with clean paper towels. DO NOT RINSE!” (emphasis theirs)
Fourth, the antibacterial properties claimed for assorted plastic products are viewed skeptically by folks such as the Association for Professionals in Infection Control and Epidemiology: "There is no proven infection prevention benefit in the use of these products. APIC does not advocate the use of antimicrobial household products which are marketed with the implication of preventing infections.
Fifth, the information I have on bleach safety is that mixing it with ammonia creates chloramine gas, and mixing it with acids creates chlorine gas. I’d have to dig up my old organic chem textbooks to figure out exactly how it all works. The bottle of Clorox I just looked at says not to mix with “toilet bowl cleaners, rust removers, acids, or products containing ammonia”.