Several service providers offer hosted Exchange Servers for a small monthly fee. Call to make sure that the provider offers either Exchange Server 2003 with mobile extensions or Exchange Server 2007, and ask whether users are allowed access to Exchange Server's management console. Without management console access, you can't remotely blank your phone.
Apple designed the iPhone as a consumer device, so it's heavy on convenience and light on security. If you want protection, you have to accept some pain. Fortunately, it doesn't take a lot of time or tech savvy to keep what's in your iPhone for your eyes only. The oft-repeated recommendations alluded to in the beginning of this story are all worthwhile, but if you augment them creatively, you'll befuddle the bad guys with techniques they hadn't considered and that don't yield to automated cracks. Never overlook unorthodoxy as a means of protection.