The most popular antenna for homebrewing is the 2 meter J-pole.  They may even have a low SWR on 70 cm, though their high angle of radiation makes them poor performers.

• The DBJ-1: A VHF-UHF Dual-Band J-Pole 
  Feb 2003 QST
  Searching for an inexpensive, high-performance dual-band base antenna for VHF and UHF? Build a simple antenna that uses a single feed line for less than $10.
• A True Plumber's Delight for 2-Meters - An All-Copper J-Pole 
  ARRL Antenna Compendium Volume 4, pp. 195- 197
• An Easy Dual-Band VHF/UHF Antenna 
  QST September 1994, pp. 61-62
  A J-Pole for 2-meters and 70-cm.
  Feedback QST February 1995, p. 56. (included in PDF file above)
• A VHF-UHF 3-Band Mobile Antenna  
  QST February 1980, pp. 16-17
  Three bands - 144, 220 and 440 - on one stick, a triband J-pole.
• A 146- and 445-MHz J-Pole Antenna  
  QST October 2000, pp. 50-53
  The total materials cost is about $21, and only common hand tools are required.
• Construct a Simple 5/8-Wavelength Vertical Antenna for 2 Meters 
  QST September 1980, pp. 22-23
  No loading coils - inexpensive - easy to build.