Backpack strollers

I've been looking for backpack strollers (ie: one that converts from a stroller to a backpack when needed).
Here is my research: See http://parents.berkeley.edu/recommend/where2buy/strollerbackback.html

• Evenflo Hike 'N Roll child carrier backpack/stroller (ebay 110012476140 US$30) [discontinued?]
  
  
  
  
  
  


• InSTEP Stroller Backpack SB100AB Standard Stroller US$60-85


• InSTEP Deluxe Stroller Backpack SB150 Standard Stroller US$90


• Kelty 2004 Convertible Stroller Backpack Carrier US$135-145
  


• Sports Kids stroller backpack US$62


• Kool Stop Stroller Pack Backpack Free Shipping KS-PACK US$188 (fits in airline)


• no-name stroller from ebay: 2 wheels & rather shaky looking stick (ebay 270017403094 US$10)