There goes another Karma point. Cannot agree more. While copying Gerber files, layouts, etc. published by switch mode regulator component manufacturers can yield perhaps the desired results, these types of devices are inherently more difficult to implement than most folk seem to give them credit for. Which brings up a good point, i.e. how confident is anyone re: the layout practices and EMI / EMC compliance of boards sold on Ebay?
While I briefly considered the switch-mode route for a design I've been working on, I ultimately decided to keep it simple, not extract every mWh from the battery pack and simply run my rig straight from a Lipo battery.
Coming back to the request from the OP, I'd buy from a reputable vendor, i.e. one that has put the time and resources in to ensure the switch mode power supply is going to work properly. Or, consider adding an additional power supply that simply takes line power instead. USB chargers are very inexpensive now and reputable brands don't cost an arm and a leg, yet offer 1A+ charge performance at 5VDC.