Maybe a python guru may help you. In C the function to call is MeeGo::QmDisplayState::setBlankingPause(). A simple script that you start in the background might do the job.
$ gconftool-2 -a /system/osso/dsm/display possible_display_dim_timeouts = [15,30,60,120,300] color_profile = Neutral use_low_power_mode = true display_blank_timeout = 5 possible_display_blank_timeouts = [3,10,15] display_brightness = 3 adaptive_display_dim_threshold = 3000 display_brightness_level_step = 1 display_dim_timeout = 30 max_display_brightness_levels = 5 inhibit_blank_mode = 0 als_enabled = true use_adaptive_display_dimming = true
$ gconftool-2 --type list --list-type int --set /system/osso/dsm/display/possible_display_dim_timeouts [15,30,60,120,300,10800]
$ gconftool-2 --type int --set /system/osso/dsm/display/inhibit_blank_mode 1
$ gconftool-2 --type int --set /system/osso/dsm/display/inhibit_blank_mode 0
gconftool-2 --help