Interesting... I have always done two batch sparges. Do you get high efficiency doing a single sparge? That would certainly cut out some time on brew day... half an hour or so anyway. Certainly my second sparge is getting a lot less efficency as compared to the first which is clear even just from the colour of the wort.
As for moving the boil pot with hot wort, I don't see that as being a problem for me. I cook on a propane burner and cool with an immersion chiller and then just open the value on my brew pot and have the wort splash down into my primary. The only moving I do is to lift the brew pot from the burner to a higher table after it has cooled to maximize aeration from the splash.
Thanks for your comments. I'll have to think about it. I was hoping not to have to upgrade much to go 10 gallons so it isn't as attractive if I need a new mash tun as well. I already have a pile of dough into my homebrew equipment!