Tube amplifiers are a popular project among hams.  Many hams like the challenging of hunting for parts to build a high quality amplifier out of inexpensive surplus parts.  Keep in mind that the before 1982, the FCC regulated hams according to input power, so when hams talk about a 1kW amplifier, they are referring to 1kW input, not output.  Few of the older amplifiers will handle the modern legal limit of 1.5kW.

• Using Solid-State Transceivers With Older Tube Amplifiers
  A collection of Hints and Kinks from the pages of QST
• How to Test and Align a Linear Amplifier 
  QST May 1952, pp. 39-43, 128
  Alignment procedure for an old tube type SSB amplifier.
• How To Run Your (Tube Type - Ed.) Linear 
  QST November 1962, pp. 11-14
  What it can do and what it shouldn’t do.
• A Single 6146 Amplifier (one 6146, 70-90 watts) 
  ARRL Handbook 1959, pp. 196-198
• An All-Purpose 813 Amplifier (one 813) 
  ARRL Handbook 1959, pp. 199-201
• A Compact 650-Watt Amplifier (two 4X250B)
  ARRL Handbook 1959, pp. 205-209
• 4-250-A's in a 1-Kw. Final (two 4-250A) 
  ARRL Handbook 1959, pp. 210-214
• A High-Power grounded-Grid Amplifier and Power Supply (one 3-1000Z) 
  ARRL Handbook 1968, pp. 199-204
• One-Band Kilowatt Amplifiers (two 813) 
  ARRL Handbook 1968, pp. 195-198
• A Compact 3-400Z Grounded-Grid Amplifier (one 3-400Z) 
  ARRL Handbook 1968, pp. 191-194
• An 811-A 200-Watt Grounded-Grid Linear Amplifier (one 811-A) 
  ARRL Handbook 1968, pp. 187-190
• Using 2 3-500ZS In grounded Grid 
  ARRL Handbook 1971, pp. 201-204
• A One-Kilowatt Amplifier Using A 3-500Z 
  ARRL Handbook 1972, pp. 182-186
• The SS-2000 Amplifier (one 3-1000Z)  
  ARRL Handbook 1972, pp. 178-182
• A Sweep-Tube Linear Amplifier (four 6KD6) 
  ARRL Handbook 1972, pp. 176-178
• A 160-Meter Amplifier (two 572-B)  
  ARRL Handbook 1978, pp. 184-186
• A Conduction-Cooled Two-Kilowatt Amplifier (two 8873) 
  ARRL Handbook 1978, pp. 186-190
• A Two-Kilowatt Amplifier Using the Eimac 8877 Triode (one 8877 or 3CX1500)
  ARRL Handbook 1978, pp. 190-195
• 1500-W-Output Amplifier for 160 Meters (3CX1500A7) 
  ARRL Handbook 1990, pp. 30-46 to 30-49
• A Legal-Limit Amplifier for 160 through 10 Meters (8877) 
  ARRL Handbook 1990, pp. 30-50 to 30-57
• A 160- to 10-Meter Amplifier Using the 3CX1200A7 
  ARRL Handbook 1990, pp. 30-58 to 30-63
• The LKA-1 Linear Amplifier (two 4CX250B) 
  QST June 1975, pp. 39-43, 158
• A Table-Top Half Kilowatt (two 811A) 
  QST January 1960, pp. 24-27, 156, 158
• The RCC 230-L Amplifier (two 807s, 230 watts)
  QST February 1963, pp. 29-32
• A Compact High-Power Linear (four 811A) 
  QST June 1961, pp. 11-14
• An 800-Watt P.E.P. Input Linear (two 7094)   

• Bill Beech, NJ7P has a tube database on his web site.
• Comprehensive Transmitting Tube Data
  1988 Handbook Base Diagrams and Data

• Ian White, GM3SEK, sells kits for tube control and protection.  They are of particular interest to hams building tetrode amplifiers, which have more complicated biasing circuits than grounded grid triodes.