Great to see Infinitecoin increasing in value at Coins-e and being up there on those profitability charts! The good thing about increasing difficulty is that higher difficulty indicates more interest in Infinitecoin.  Also, as difficulty increases, the security of the IFC network increases.  

They already exist in the form of the two Infinitecoin P2Pools  - P2Pool uses a (slightly advanced) form of PPLNS  TreasureQuarry, for example, uses an N value of 8640 (shares), which is a general standard for most P2Pools.

One of the main differences compared to traditional pools is that the difficulty of shares adjusts dynamically depending on the P2Pool's total hashrate, so that shares are spaced out over a certain period (similar to the way that the difficulty of Infinitecoin adjusts depending on the global hashrate).  Often this period is 10 seconds between shares, which equates to 24 hours for all 8640 shares to "pass by", but many pools including TreasureQuarry use a slightly longer share period which has the benefit of reducing DOAs.  

Thanks to the P2Pool wiki for this quote..."Each share contains a generation transaction that pays to the previous n shares, where n is the number of shares whose total work is equal to 3 times the average work required to solve a block, or 8640"..."whichever is smaller. Payouts are weighted based on the amount of work each share took to solve, which is proportional to the p2pool difficulty at that time."