Gabe,
Gmail is an imap style server, so your mail stays on the server until you delete it. Your Gmail app has the ability to limit the number of days to sync to your phone. There should also be settings to show or not show pictures and to download or not download attachments. Regardless of mail app, it is going to sync, at a bare minimum, the header of the available messages. One option that you do have is to turn sync off for your gmail account and then only turn it on when you want to check your mail. I would think this would really be a pain, but if you set the gmail app to only sync 1 day's worth of e-mail, you could turn on sync, deal with the messages that have come in since the last sync and then turn sync back off. I'm not even sure if the above is doable, but I would think you could if you wanted.
Its doubtful, but I hope this helps,