Cryptonomist, your node is handing out a difficulty of around 300k to your miners. The expected number of hashes needed to find a 300k diff pseudoshare is 300000*2**48/0xffff = 1.28 PH. With a hashrate of 80 GH/s, it's expected that would take about 4.47 hours per pseudoshare. Since p2pool needs to switch jobs every 30 seconds or so, that means that 99.82% of the time, p2pool would switch jobs before your miner found a (pseudo)share.

I suggest you manually set a lower pseudoshare difficulty (e.g. 256, for about 14 sec per) by putting address+256 as your stratum username. This will only affect your stats, not your revenue. You can also put address+256/32768 to set your share difficulty target to either 32768 or the network's minimum share difficulty (whichever is higher) if you want to have a better chance of mining an actual share.

Ideally, I would tweak my p2pool code so that it would adjust pseudoshare difficulty more quickly and intelligently to miners with different hashrates. However, that's pretty low on my priority list right now, since it does not affect revenue or resource requirements at all.