Can you lengthen jeans?

I have a pair of 501s that I picked up in some charity shop for a couple of quid last week.

They're basically great, but could do with being maybe one third/half an inch or so longer. This is probably truly stupid, but what with everything being so clever these days what with mobile phones that have built-in Soda Streams and all that I wondered whether genius tailoring types could do this somehow?