Elite does look nice, but the open-source clone of it called Vega Strike uses OpenGL and I don't think OpenGL libs have been ported over yet...if ever.
And it weighs in at a little over 200MB for the Linux release.
If you like Elite - or Starflight - then check out ArnimS's port of Star Control II on his website.
There's also ggelite but this one is also dependant upon OpenGL.
Until someone ports the OpenGL libs - if possible - over to the N770/N800 we're kind of hamstrung on what can be ported over.
You can also take a look at TINE as well.
For Boulderdash take a look at Epiphany. It's SDL-based and looks like it will fit real well on the IT's screen.
I like the way Timewarp looks myself. It's like Star Control but with better ship graphics.
No one's ported xpilot yet?