I know this is an older thread, but the world of appliances have changed since the original post, so I want to share my perspective with that in mind.
For most kitchen appliances (toaster, microwave, etc.) you're not going to get much real performance differences between UL and CE specs, not unless you care deeply how much quicker water boils in a 2000W kettle (pretty much the max in US) and 3000W kettle (much more common in the UK). For normal people, I'm sure you can plan your morning routine around a US toaster that takes 30 seconds slower at making your breakfast.
There are some niche cases - high end espresso machines or raclette cheese melter come to mind - where the CE version isn't necessarily more powerful, but they come with additional premium features that aren't available in the UL version. In these cases, you can try a generic step up voltage transformer, but if the unit comes with any type of digital thermo-electric control circuit (which is very likely) you run the risk of the device unable to regulate temperature accurately, leading to higher risk in thermal runaway failure or premature heater burnout. As always, caveat emptor.
The stand-alone induction stove is the only case I can think of where the performance difference between UL and CE is real and substantial. The power deficit between the two standards make a huge difference in high heat searing or stir fry recipes that longer cooking time cannot adequately compensate. Even the US version of the Breville Control Freak - a $1400 top of the line induction cooker - is rated at 1800W, barely over half the power output of a generic 220V professional induction stove at 3500W.
Some businesses or laboratories that need to test or run overseas appliances install high power frequency and voltage inverters, but that's usually planned and built into the lab, which requires a lot of engineering drawing/approval/OSHA/insurance paperwork and premium just for the luxury of a delicious homemade kung pao chicken dinner (also, good luck finding an electrician willing to wire your home kitchen without the paper work). Moreover, high power induction stoves designed to UL standards are increasingly available, even if they are still expensive.
Bottom line, it's just too much hassle, too expensive, and not worth the real world difference to wire my kitchen for 220V appliances.