Got my Fire in early Dec from a seller based in China. (The first one I bought from another China seller didn't ship it after 4 weeks as he claimed it was out of stock & I got my money back through PayPal after I lodged a complaint). My serial no. ends in 9038, build no. 20120907.tm, a late production unit but still experienced the non-responsive touchscreen issue after about a week of use. Had no choice but to send it back to the seller who thankfully was quite responsive.
Got it back after about 3 weeks(came fully charged but without the original box & warranty card that I had sent it back with). The following were noticed -
1) Android v.4.0.4, Kernel version 3.0.8-gc0699a5, visual.zhang@droid05-sz #6, SMP PREEMPT Tue Dec 11 15:22:53 CST 2012. Build number 20121211tm
2) the clicking sound when tablet is not in use is no longer heard (good!)
3) other common reported issue of tablet suddenly shutting down when battery level was around 20% happened once (not good!)
4) so far have charged it twice using a Belkin Conserve Valet charging station - http://www.belkin.com/us/p/P-F7C008 (Think the output is 1A.) No issues with touchscreen so far *touchwood!* (great!)