I remember a pure
GSC list placed in an event back in October.
Link
The basic skeleton is a fairly mechanized list with the standard 4-Armed Emperor melee detachment and a more unusual mixed creed detachment (Rusted Claw for Drive-by Demolitions and Hivecult for vehicle support).
I do think that is probably one of the largest hurdles facing the army at the moment from a data collection and playability standpoint. The current rules strongly encourage leaning into the army's mechanized elements and punish ambush-heavy play. Unfortunately, most competitive lists in 8th (and 7th for that matter) tended to forgo vehicles entirely, so I imagine most people probably shelved their armies in hopes that the 9th edition codex will make ambushing viable again rather than spend money and time redesigning their armies from the ground up.