Dedicated 19" (tube) Poweramps
This is a list of 19" poweramps. There are some 19" rackmountable ampheads as well, but they do not qualify as a dedicated poweramp.

Brunetti:
Silver Bullit   120 watt, 4x EL34, 3U
Van Der Graaf   2x 100 watt, 6550 tubes, 4U
Rockit   2x60 watt, 2x5814a tubes, 1U

Carvin:
Tube 100   2x50 watt, EL34, 2U  *

Seymour Duncan:
KTG-2100   100watt, kt-88  *
KTG-2075   Solid State, stereo  *

Engl:
E840    2x50 watt, 5881, 2U
830/30   2x30 watt, EL84, 2U  *
830/50   2x50 watt, EL84, 2U  *
920/50   2x50 watt, 3U  *
920/100   2x100 watt, 3U  *
930/60   2x60 watt, 6L6GC, 3U
930/120   2x120 watt, 5881, 3U

Ernst:
The Traveller   2x100 watt, EL34, 4U  

Groove Tubes:
Dual 75   2x50 watt, EL34/6L6/6550/KT88, 5U
Soul-O-75-Slave-Amp

Hughes & Kettner:
VS 250   2x50 watt, 8x EL84, 2U  *
CF 200   2x100 watt, 1U, solid state  *

Kitty Hawk:
2x50 watt   4x EL34 *
2x100 watt   8x EL34 or 8x 6550 *

London Power:
Studio   2x100 watt, 3U, EL34/6L6/6V6/6550/5881/6CA7
Stereo 50   2x50 watt, 3U, EL34/6L6/6V6/6550/5881/6CA7

Marshall:
EL34 50/50   2x50 watt, 4x EL34, 3U
EL34 100/100   2x100 watt, 8x EL34, 3U
EL84 20/20    2x20 watt, 4x EL84, 1U
MR-9100   2x50 watt, 4x 5881 or EL34, 3U
MR-9200   2x100 watt, 8x 5881 or EL34, 3U
MR-8008   2x80 watt, solid state, 1U  *
MR-8004   2x40 watt, solid state, 1U  *
VS 120/120   2x120 watt, solid state
9005   2x50 watt, 4x EL34, 3U  *
9060   2x300 watt, solid state, 2U  *
9040   2x200 watt, solid state, 2U  *

Mesa/Boogie:
2:90   2x100 watt, 8x 6L6GC, 2U  
Simul 295 Stereo   2x100 watt, 8x EL34 or 4x EL34 + 4x 6L6GC, 4U  *  
Simul 395 Stereo   2x100 watt, 8x 6L6GC or 6x 6L6GC + 2x EL34, 2 channels, 3U  *  
Strategy 400 Stereo   2x150 watt, 12x 6L6GC or 8x6L6+4xEL34, 4U  *  
Strategy 500 Stereo   2x150 watt, 8x 6L6GC + 4x 6550, 2 channels, 3U   *  
Fifty-Fifty   2x50 watt, 4 6L6GC, 2U
Twenty/Twenty   2x20 watt, 4x EL84, 1U  
Collosium 300   2x200 watt, 12x 6L6GC, 4U  

Peavey:
Classic 50/50    2x50 watt, 8x EL84, 2U  
Classic 100/100   2x100 watt, 8x 6L6GC, 3U

ReuSenzehn:
Slave 200   2x100 watt, 8x EL34, 3U
Slave 100   2x50 watt, 4x EL34

Rivera:
TBR 3 Hammer 120 Stereo   2x60 watt, 4x EL34, 3U

Rocktron:
Velocity 300   solid sate  *
500   solid state  *
250   solid state
100   solid state
VelocityValve   tube poweramp

Trace Elliot:
G-PA 80   no tubes  *?
G-PA 160   no tubes  *?

Tube Works:
1160 MosValve   2x80 watt, 2U, solid state
1500 MosValve   2x250 watt, 2U, solid state
MosValve 500   2x250 watt, 2U, solid state  *

VHT:
Two-Ninety-Two   2x100 watt, KT88, 2U
2/50/2   2x50 watt, EL34 or 6L6GC, 2U
Stereo 2150S   2x50 watt, KT88/6550, 3U  *
Stereo Classic   2x50 watt, EL34/6CA7  *
Stereo 200 Classic    *