This is a great solution that has helped me immensely.
When using Google Apps for Business you are instructed to set up the account on your iPhone as an MS Exchange type so that it will sync calendar and contacts. But the mail app on IOS doesn't transfer the flag status properly going from the phone to the Google Apps account. So you can star something in the gmail interface and it will show up as flagged on the phone, but you can't flag or unflag something on the phone and have it show up in the web interface. So I was constantly having to scan my phone for things I had flagged as important on the road, because they wouldn't show up on my computer. This was made worse because up until yesterday with IOS 6 there was no easy way to see everything that you had flagged on the handset.
So setting up the Exchange account to do calendars and contacts, but no e-mail is great.
Then set up the same account as a gmail account with only e-mail services.
Perfect!
(until Apple just gets flagging working properly! I'm not going to hold my breath, it's been IOS 5 and now 6 with it broken for me)
Thank you very much for posting this. It's so obvious it makes me wonder why I didn't think of doing it before.