(edited) Thanks for triggering me to retest this module ;-)
Some quick testing on the drupal module Editable Views for D7 shows this now works.
Note1: site tested on also using CiviCRM Entity so this may be a requirement.
It worked for me for eg First Name and a custom text field and a custom radio though it only showed Value not Label for the options.
Steps:
add/enable modules (of course)
set View up based on civi contact (for my testing purposes)
add new field and choose CiviCRM Contacts: Entity metadata property (editable)
this includes a new dropdown called Metadata property where you can then select eg First Name, or a custom field
Save field
hey presto
Wasn't super fast in saving but that might be my dev system
Note1 if this is awesome but needs a bit of love in terms of eg multichoice Label v Value, then either the CiviCRM Views code needs a tweak or CiviCRM Entity does.
Note2 there is new work going on to extend CiviCRM Entity currently (see blog) so if it is something you can help fund to happen it would be good to reach out on that project.