Sometimes the low tech simple solution is hard to beat. Although I have an Anker 10ft cable and it works for me but you don't get the right angle connection.An extension is probably the way to go. The issue is the power supply. I used a longer USB cable with a garden variety USB 2-prong plug and it didnt charge.
Ahh, works for a SP3 but not a S3 the little power brick plugs straight into the outlet.Here you go.
Figure 8 - Longer power cord
Power Cord to Power supply Issue | Microsoft Surface Forums
I do actually have my S3 brick at home plugged into an extension cord.Yeah, I'm an idiot, sorry. I forgot the cord is not hard wired into the power supply. I'll just buy an angled, longer USB->Micro USB cable. Duh.
It's not my machine, it's wifey's, so I haven't looked closely at it in a while.