Firstly the images you aspire too are 360x180 not 360x360 (I believe that was an iP*x marketing thing) You can pan around 360 degrees and pan up 90 degrees and pan down 90 degrees making the 180.
One-Shot lenses are usable for low quality panoramas and should not really be displayed larger than maybe 640x480 with 400x300 the norm. The one-shot lens has it's place, but has never been for high quality nor full screen display.
I suggest you use your D80 and a Sigma 8mm Fisheye or Nikkor 10.5mm Fisheye. Also the Tokina 10-17mm Zoom Fisheye is an option. You will need a good panorama head and I suggest and recommend Agnos MrotatorTCPS.
The stitching software is important and what you have most likely does the job fine (although I have never used it) I use Panoweaver 5.0 and PTGui for some tougher projects. For speed you really can't go past Panoweaver 5.0 If you are to be doing "tours" Tourweaver 3.0 is the best on the market still. Even after the latest release of the "so called" opposition.
I had a play with the "Scripts" you suggested in the first post of this thread and I have to say it is very good at what it does. (Being Free or Donate-ware) makes it good value. I still personally have no real use for it in my workflow.
When it's all said and done the equipment and software is only the start. Knowledge and experience is a vital ingredient. Photographers take beautiful photographs, Real Estate agents take pictures! Some are very good at blending the two.....