mate, trust me you dont need a keyboard to do riffs... sure, its a useful tool if for toying with ideas, but its not essential... lets face it most stuff your gonna be writing is too fast to be played by hand anyway... unless of course your a champion five knuckle shuffler like myself... just write in a few notes, loop em up and start fiddling... then clean up after yourself and move some notes around too.
trilogy? yes mate! probly going to hindsight first but i'll b there before natron starts, believe!!! see you there mate.