I stumbled across the company Stockpile.com when searching for gifts for a dear friend’s teenage daughter, but it also makes a great gift for someone traveling too.
Through their website you can purchase stock in hundreds of companies in the form of a gift certificate. As it can be bought in monetary increments, you can purchase factions of a stock.
If you have no idea what stock they want, buy a generic gift card and let them pick a stock for themselves.
The website is very easy to use, even for someone who has never owned stock before.