Some results after testing 0.9.2.7

W3TC 0.9.2.7 + WPTouch = Fail even with the user agents tricks
W3TC 0.9.2.7 + heavy load = Database cache fail

W3TC 0.9.2.6 + WPTouch = Fail even with the user agents tricks
W3TC 0.9.2.6 + heavy load = Database cache fail

W3TC 0.9.2.5 + WPTouch = OK
W3TC 0.9.2.5 + heavy load = OK

Reverted back to 0.9.2.5, everything is fine.

Server is VPS hosted @ Planethoster
Apache 2.2.23
PHP 5.3.20
MySQL 5.5.28-cll
cPanel Pro 1.0 (RC1)
cPanel 11.34.1 (build 7)

http://wordpress.org/extend/plugins/w3-total-cache/