There is a way, which is to integrate a platform made mostly of open source. The first Fremantle SDK will be 100% open source (missing some components and features certainly, but being functional and buildable).

Didn't Android run on the N810 before the G1 was launched? It's a similar story.

But it's good to have the expectations right. What your friend has probably in mind is a full fledged Maemo 5 SDK with the final look&feel and all the Nokia apps available under emulation. Something that would provide the code to hack a full Maemo 5 image with applications and etc. This is not the point of the SDK and this is not going to happen - at least not in the release we are preparing right now.

This first Fremantle SDK release is going to be a rough shot of fresh code targetting mainly platform developers. The API won't be complete, leave alone frozen, so not even application developers will find much real use of it. Power/general users will be able to do very little with this SDK, apart from reading what (we hope) the most advanced developers will interpret and write about.

This might deceive some of you willing to have Maemo 5 in your hands, but this is how open development works.