Yes, indeed.

When Nokia recently unveiled the touchscreen version of S60 (first phones due out in 2008), one of the main selling points is its support for tactile feedback when you select something:

http://www.allaboutsymbian.com/news/...e_Launched.php

This general topic is definitely the missing piece of the mobile interface jigsaw puzzle, a way to get the best from both touchscreens and keypads. I don't know who will do it first or get it right first, but eventually we will see some kind of feedback as a standard feature of touchscreens.