Support for Increase from 32,000 to 128,000 Characters
Text in an email that is over 32,000 characters is automatically truncated to 32,000 characters by On-Demand Email-to-Case. Your Salesforce.com representative can raise this limit to 128,000 characters with Inbound email for your organization if necessary. Email to Case Premium will automatically use this increase for inbound messages once enabled by salesforce.com.