NATing Google Voice calls, Dynamic numbers

I had a stupid idea when I called from a gMail account without a number attached to it, by mistake, but anyhow the caller ID ended up being +17607058888, so I tried calling it back but the recording said "we couldn't complete your call, please try again." So I did but with the same result. Wouldn't it be cool if you could call back the gMail account that last called the number that is calling back? I know that this could lead to errors, but the current situation, where you can make calls from gMail, but then you miss the call and call back, isn't as good as it could be. Maybe they could even have a pool of numbers to auto assign as callback numbers, just like DHCP recycles IP addresses once you logout. Anyhow since I do have a Google Voice number, I can make that call again, but if you ever want to make a call that you can't be called back on, use gMail.