Besides Samsung and Panasonic, will any 08 RPTVs have long lasting light sources?

Since the 2007 models have only recently started shipping I think you will have to wait till the 2008 Consumers Electronic Show (CES2008) the first week in Las Vegas the first week of January to find out.

The new models get shown to the dealers in January and they are all normally all out by August in order to be in the stores before football season starts. Sometimes a vendor will realease some in early November that they could not get out by August but which they did announce the previous January that they were coming and they want to get them out for the Holiday Buying Season.
I beleive that the Sony XBR3s will come out this fall just like the XBR2s did last fall and I believe one vendor (I forgot which) will have a laser DLP out by the holiday season.
You can probabaly google on
CES 2007 HDTV
and find some reviews of the products that were announced this past January.

Late last summer or early fall (2006) Mits demo'ed a DLP RPTV with a laser diode light engine that was claimed to be a step beyond LED light engines and they said the production model will go on sale for the Xmas shopping season of 2007. I haven't heard anything new on this in the past several months, but Mits may still be on track to begin shipping in the 4th quarter of this year.

My guess is Toshiba will either abandon their rear projection line in 2008 or intoduce models with a non-bulb technology. It likely won't happen in the fall; the 2007 models became available in early April. But Toshiba did it without fanfare - no press release, and no Cinema Series (MX) models.