Well now that T-mobile have pushed out the OTA update for the G2 Touch (HTC Hero), I’ve got Android 2.1 and can connect the phone to 2 Google accounts without a problem.
The only minor problem was that the widget for the Gmail inboxes looked identical and didn’t display unread counts.
These two problems were fixed with this great widget by Alexander Blom, there’s a barcode to jump to the marketplace entry on his web page.