joshi tm:
It is NOT the most popular variation, but many of those that like Open Rush also like Corner.
Your proposal is different in a significant way to the Corner variation at IYT. There, the setup includes an additional diagonal for each player with 8 more pieces than you proposed.

Dark Prince: do you think it may be worth exploring?

Nothingness:
joshi tm:
I have read other posts expressing interest in a corner variation.
I would think it worthwhile to find out how many others would like such a variation and discuss the parameters with those interested.
For me, the Corner variation at IYT is an equal favorite with Open Rush. I play those 2 variations almost exclusively.
As to the parameters here, I would consider Joshi's 7 diagonal proposal as well as possibly an 8th diagonal.
If only 7, we might consider removing a 1 and a mine or a 1 and 2 as Joshi suggests.
If 8 diagonals, we might instead consider adding additional pieces and/or leaving squares within the 8x8 setup triangle unoccupied.

Dark Prince:
I also liked the corner version at IYT. I quitted the site because there wasn't anymore a message board and a lot of good players moved to BK.
I suggest a corner version with a 9x9 board, that would be in the middle between Open Espionage (10x10) and Small Espionage (8x8).
We should meet the requirements of a lot of players.

dAGGER:
Sounds good, and it could use the 7x7 triangle setup zone suggested by Joshi.
x x x x x x x - -
x x x x x x - - -
x x x x x - - - y
x x x x - - - y y
x x x - - - y y y
x x - - - y y y y
x - - - y y y y y
- - - y y y y y y
- - y y y y y y y