Skimming through all the comments, perhaps you would be better off with a single larger genset that is intermittently run to both supply sync'd AC and charge batteries in your system. And probably beef up the battery storage a bit.
In a config like this, the PV/Wind/Batteries will suffice for a certain number of days/hours, then the genset is operated for a period (eg, 8 hours) to top the system up.
Less components to source, anyway.
And for your info, perhaps you might look at the "Sunny Boy", "Windy Boy", "Sunny Island" series of inverters from SMA.
The sunny/windy boys are basically grid-tie inverters that take your PV or wind DC and convert to synced AC. In a standalone system, you make a local grid, with the sunny island as a master inverter-charger attached to a battery bank. It then controls a genset or input from an outside grid when needed if there's insufficient generating capacity on the local grid.
The sunny island will regulate power as necessary by fractionally shifting the grid frequency to regulate output from the sunny/windy boys to match system load and battery charging needs. If the system frequency is bumped up a little, the slave inverters will back off a bit and vice versa.
Basically that combo do all that you ask, but cost becomes the issue. The main advantage is that you can do it in increments. For me, I'd probably :
- Buy sunny boy and PV array, link to outside grid and start saving cash immediately.
- Buy sunny island and batteries, unhook sunny boy from outside grid, make a local grid and attach sunny boy to it, then link sunny island to both local grid to supply power and the outside grid to charge batteries when PV input is insufficient.
- Buy genset and discard outside grid, or make it manually switched, or switched at off-peak rates if you've got them.
- Buy windy boy and wind generators whenever cash permits it for supplemental power.
Another advantage of this is that someone else has done all this before and you don't have to dick around as much :-p
See http://www.sma-america.com/solar-technology/products/island-grids/battery-inverters/index.html
and a PDF that describes the system at
http://download.sma-america.com/smaprosa/dateien/1353/SI4500-11-BE2306.pdf
If you really want to wrap your head around it, go download the install manual for the SI-4500 from that site.