need longer trips (>10 miles) for cold engine,

[bzipitidoo]

I just can't get good mileage when I start out with a cold engine and only go 10 to 15 miles. Winter makes it worse, but I see it in summer too. Temperatures where I'm at have been around 40F now, and often hit 100F in summer. I've got a Metro (automush tranny unfortunately), and on a 10 mile trip, all city driving, starting out cold, I'll see 28 mpg or so at first and gradually climb to 35 mpg by the end of the trip. If the engine is warm from being driven recently, and I take a 10 mile trip then I start off already at 33 mpg and end at 40 mpg or better.

That's a pretty big difference. I thought of maybe trying a block heater, but I'd need that engine nice and hot, say, 140F minimum. I have the impression block heaters are only intended for very cold climates to get the engine up to maybe 50F tops. So, what to do? Store in hot garage best I suppose, but that's not easy, and is no help for coming home from wherever I went. Some of the crazier thoughts was wrap the engine in insulation? Pour very hot water over the engine before I start? Paint the hood black? Anyone have some more practical suggestions?