Making A Rom From A Game ?

[crea]

Hi, my brother and I both have ds lites, and play against each other quite a bit on a few games, the prob is having to buy two copies of every darn game which gets expensive. I have seen the DS lite flash cards and things like that and wondered if it is possible to copy a game onto something like that so we only need to buy one game each time instead of two copies of everything ?. No idea is such a thing exists but it would be really handy if you could.
Thanks
Iain