I do not know taus at all but about the Malca variants, here are my propositions
Valdor (variant with big plasma gun & melta gun on right side):

- move: 15cm
- armor save: 2+ (front, not all around, in regard to Baneblades and others SHT heavy protected that do not get a All armour armor save)
- caf: +1 (valdor is not made for assault but for tank hunting)
- note: PD(1)
- weapons:
- main weapon: plasma gun
Range: 50cm
Attack dice: 1
To-Hit: 3+
TSM: -4
Note: -
- secondary weapon: 1 multi-melta
Range: 25cm
Attack dice: 1
To-Hit: 3+
TSM: -2
Malcador (anti personal variant):

- move: 15cm
- armor save: 2+
- caf: +4
- note: PD(6)
- weapons:
- main weapon: demolisher cannon
Range: 50cm
Attack dice: 6BP
To-Hit: 4+
TSM: -1
Note: Ignore Cover
- secondary weapon: Las-guns
Range: 75cm
Attack dice: 2
To-Hit: 5+
TSM: -1
Malcador (twin las gun variant)

- move: 15cm
- armor save: 2+
- caf: +2
- note: PD(1)
- weapons:
- main weapon: demolisher cannon
Range: 50cm
Attack dice: 6BP
To-Hit: 4+
TSM: -1
Note: Ignore Cover
- secondary weapon: mounted weapons
Range: 75cm
Attack dice: 4
To-Hit: 5+
TSM: -1
Malcador (battle cannon variant):

- move: 15cm
- armor save: 2+
- caf: +2
- note: PD(1)
- weapons:
- main weapon: battle cannon
Range: 75cm
Attack dice: 1
To-Hit: 4+
TSM: -2
Note:
- secondary weapon: lasguns
Range: 75cm
Attack dice: 3
To-Hit: 5+
TSM: -1
About the tanl hunter vampire, Mogwaï posted a profile last year if I remember well

I did not really like it due to the holo-fied on it but it could be tested.