Conversions:

• The fully-rigid part can be gotten by attaching a rigid 26" fork to a 26" hardtail frame.
• The single-speed part:
  • chain tension is a no-brainer if the frame has horizontal dropouts. If you have vertical dropouts, you can use a chain tensioner.
  • the rear hub can be converted to a SS from a geared one, if needed

• Surly
  • 1x1
  • Pugsley
• Salsa Cycles
  • Ala Carte