In Germany we have (as I'm sure you know) lots of vegan sausages/ready-made-food. Especially the ones by VeggieLife/Viana keep very well without refrigeration because they're made from a mix of soya and wheat gluten.
Viana (Picknicker etc) and Wheaty (RedHotChiliPeppers etc)also have some that don't need refrigeration at all.
There's even vegan ravioli in a can.
See some products here, I'm sure you know most or all:
- bread with whatever spread you like
- muesli/oats/cornflakes etc with soy milk or juice
- homemade cake
- biscuits, homemade cookies/bars, etc
- Alpro desserts
Some festivals seem to have good vegan food stalls, see for example pictures from Wacken 2011: http://www.christiankoeder.com/2011/08/wacken-2011.html
Just take some packaged stuff, and stuff you like ;) Don't force yourself to eat sth super healthy ;)