Havent seen a 1-2kw diesel one, seen a 2.5kw diesel, aircooled, noisy beast.
Aux engine, yes you can get a genny to fit, a big alternator, 1-5kw. So that would be OK, Albeit a tad expensive.
Easy peasy....... we fitted a mastervolt 3.5 kw gen by cutting off the last 2 steps of the companion way steps and fitting the gen there, bolted to bearers bonded to the hull, so it didn't stick up too far into our accommodation. Now we can run loads of lovely electrical things like microwaves, hairdriers, fan heaters, lights, the watermaker, water heater and battery chargers.
Makes for easy cruising in comfort.
The gen isn't very big, produces a steady up to 2.5Kw so you sometimes have to switch things off. But really great when away.
Don't go for something too cheap. Once you have tried the comforts of mains leccy, you will really miss it if if packs up on you. Get a well tried make with a god reputation.
At least that is what I think /forums/images/graemlins/tongue.gif