Actually, with a fair bit of work, this may be possible?

Google releases all sources for Android apparently, & there's a popular minimalist custom ROM called CyanogenMod (read more from wikipedia).
It's available for many Android handsets.

So anyway, it would be possible to remove the top Android layers from those ROMs, then make maemo talk to a custom built maemo-JNI layer, that in turn interfaces to Androids hardware abstraction layer?
(yea this is a bit dumb, but you'd get the radio modules, etc?)

Or alternatively, maemo would use kernel modules on those android handsets directly, where i imagine maemo would then have access to many capabilities already?

Anyway, all high level fluff...

I bought a Droid 4, flashed with CyanogenMod & had been looking at articles to bring same level of n900 functionality to droid 4... so far not very near that...
Some folks may be interested to read a bit about this tho:
http://whiteboard.ping.se/Android/Debian

Seems like a lot of work...
Should try boot Maemo (don't "release" anything) and try get the GUI to work.

I got some functionality (BAAAASIC!) but never got the GUI to work, tried VNC.
I gave up not long later, was a fun night or two but was not worth the effort - easier to just use the N900.