"AWA" over at the Expecting Rain TTRH forums has an interesting theory which I'll requote here...
"...Season 2 sounded like it was brought to an end in a patch work way with a brief comment tagged on the end of a show to cut it off at 25, thus it is quite logical to assume that Season 3 was recorded with Season 2, originally meant to be Season 2 as well... which would thus make perfectly logical sense that Bob would start and end what was likely intended to be the full Season 2 with "Hello" and "Goodbye".For those not as obsessively fixiated on TTRH as I am, what AWA is referring to is that Season 2 opened with the "Hello" show and Season 3 is rumored to be closing next week with a "Goodbye" show, at least according to a slip of the tongue of an XM deejay earlier this week. There's been various indicators that at least some of the shows airing during Season 3 were recorded much earlier. AWA's theory that Season 2 was originally designed as a 50-episode season, similar to Season 1, has a lot of credibility, not least being the "Hello" and "Goodbye" bookends, if we find that "Goodbye" is indeed next week's show.
The fact that two of the themes mentioned previously, Carnival and Furniture (although, as Fred noted, there is a possibility Furniture might mean Clearance Sale but unless he plays some songs about furniture tomorrow, I'll doubt that very much) likely signal some run off for Season 4 (much like how some themes listed as coming in Season 2 didn't show up until Season 3) for programming reasons."
If true, is "Goodbye" really going to be "goodbye" or just auf wiedersen? As AWA mentions, one positive note may be the two to-date missing shows, "Furniture" and "Carnival," both reported in Rolling Stone as scheduled for Season 3. If they don't air, perhaps there will be a Season 4... or maybe the two shows will become collector's Holy Grails, out there somewhere, but never found.