I think the "Saxxy Weapons" should be a replacement if you already got a saxxy

First backstab does no damage, but highlights enemy and surrounding enemies and buildings to entire team.

Alt fire cancels it all, allowing you to observe another target after a moderate cooldown.

Maybe a tagging weapon, like you can select an enemy player or building (within a range) and, as long as both you and it are alive (regardless of the distance between the 2), your entire team will see it from anywhere on the map.
It would show the tagged player that it or it's building is being tagged and who tagged him/her. Along with a "compass" similar to the stolen intel compass, leading to the location of the "tagger".

how about

+15% damage
-15% cloak duration
-20% ammo from ammo boxes
allows your team to see enimies within a short distance in your FOV (does not change with FOV settings)

how about

+ cloak regain on kill
+ 50% backstab swing
- Plays a loud sound everytime you backstab someone
- Enemys can see you from close range

引用自 HACKED BY UN!KN??OWN：

+50% Max cloak on wearer
+33% damage

-70% movement speed on wearer

You have to back stab with it or you will take 45 self inflicted damage

but it can tell you the targeted enimey's ammo count if their food items and throwables are charged and tell if their next shot will be a crit or not.

- 10 disguises
- 10 damage (backstubs also kill enemies with one hit)
+ 15 movement speed
+ 15 attack speed
when you attack an enemy with this weapon, it is highlighted for the entire team for 4 seconds, if you backstub all enemies will be highlighted for 4 seconds within a 20 m radius