Good points. Never thought about it but lack of LP is going to cost you 1% to 5% depending on card speed.
Just set your maximum scan time to 1 second. This means you'll lose a maximum of ~144 seconds of mining a day or 0.166%. You'll usually lose more effort than that from pools due to other issues (stales, bugs, network latency).
Pools can't do this because all the users would slam them. But it's a perfectly reasonable thing when running on your own. (not that running pushpool with LP locally is much of an issue).
That seems sensible to me. Long polling shouldn't be necessary for a local network at all (not that it hurts). I would argue that, even with long polling, pool miners will have more of a stales problem than solo miners.
