I'm still waiting to hear back from the utility, but I *think* we're maxed out at 3/4", since it's a 3/4" main. If that's the case we'll just have to go electric for the other appliances.
I'm pretty sure my original thinking was off, anyway. The water column given is gauge pressure, so the actual pressure drop from a 7" WC would be about 0.25/(10.5+0.5), or ~2%. Which is why the code tables neglect pressures below 2 psig.
I suspect that you could get the flow you want because the pressure is quite a bit higher upsteam of the meter. You would just need a wider pipe than what is going into the meter. Anyway the utility should know.