from what i've learnt with my Desire HD, the cpu controls are handled in the kernel i think ???
my Desire HD runs the 1ghz snapdragon cpu, thanks to some modified kernels ive managed to get it upto 2ghz!!! (although this is purely for showing off, the chipset burns out after a minute or so) stable overclock seems to be 1.8ghz...although it destroys the battery in half the time it used too!
Arm processors never really had much in the way of overclocking headroom, you might get another 100mhz or so, but given the scroll's dismal battery life i can only see an overclock being even more detrimental...
more focus should be on the software, trimming down the fat and having a nice resource sipping kernel that'll compliment the scrolls basic hardware.
i do still use my scroll, but only as an mp3 player plugged into my car stereo lol! when/if 2.2/2.3 etc is released as stable then i'll consider updating it, but for now im content with it