Its been sometime since I goto chance to post anything on the site so I thought I'd see what people thought to my attempt at Grey Knight Proxys.
The conversions pictured represent along the top row: Lord Kaldor Draigo, Grey Knight Nemesis Dreadknight and Inquisitor Karamazov.
Along the bottom row: Grey Knight Purifier, Grey Knight Purgation, Grey Knight Interceptor.
To the side a Grey Knight Stalker.
(If some one can actually tell me how to add an image as it doesn't seem to be working that would be great!)
I am also using the following:-
Standard terminators painted up as Grey Knights.
I am using the Grey Knight Terminators produced by Forgeworld for Grey Knight Command Stand and Characters.
I am also using the Grey Knight Landraiders and Dreadnoughts produced by Forgeworld.
I've only play tested the Purgation Squad ad they were interesting to play and had a unique feel not requiring an LOS to target

Grey Knight Purgation Squad
Purgation Squads provide heavy firepower in certain situations, although their small numbers are a constant danger. They usually deploy in support of Grey Knights Squads during high-intensity engagements when they could be picked off from squads if spread throughout a force. They follow a similar role to Devastator Squads in Codex Chapters. But while a Purgation squad initially bares strong resemblance to its Devastator counterpart, there are key doctrinal differences. In most Chapters, duty in a Devastator Squad is seen as training for a new recruit to experience the sights and sounds of battle. Not so in the Grey Knights, whose heavy firepower squads use far more complex, powerful, and rare weaponry. Thus, Purgation Squad Battle-Brothers are often veterans who have honed their experiences on the battlefield. Once his duties are established it is rare for a member of a Purgation Squad to see service elsewhere in the Chapter. A ranged battle stance, once mastered, is not easily set aside for closer-contact missions.
Even Purgation Squad members who have since been promoted to Grand Master or Brother-Captain still prefer to wield the long range firepower of a Psycannon. Purgation Squad members also often possess the ability to hone their minds to see through the roiling energies of the warp, perceiving their foes and guiding their shots to them regardless of what might lie in between. This astral vision allows a Purgation Squad to make seemingly impossible shots, bending the path of a projectile and even energy beams around corners, between trees, and around fortifications in mid-flight. For this reason Purgation Stands do not need a LOS to their target and ignore cover modifiers.
Troop Type Move Save CAF Weapons Range Attacks2 Hit TSM
Grey Knight Purgation
Move 10 cm, Save none, CAF 4,Weapon Psycannon, Range 50cm, Attacks 2, 2 hit modifier 5+, Save modifier -1
Notes: 4+ Psychic Save, Not effected by Daemons, Does not need a LOS to Target, Ignores cover modifiers.
Support Card Grey Knight Marines Purgation Squad
Contents 4 Grey Knight Purgation Stands & 2 Rhinos
Break Point 2
Morale 2
Victory Points 4
Cost 400