I was cross shopping the XLR-V with the SL55 AMG and saw that the SL55 has a "Pop-up roll bar" that deploys if it detects a rollover. The bar can also be lowered and raised manually. Does the XLR or the XLR-V have anything similar? What happens to the XLR or XLR-V in a rollover? Pancake?

Yes, pancake.

Isn't that what the roll hoops behind the seats are for? It is similar to the Mercedes SLK, the Porsche Boxster, the Audi TT, the Mini convertible, the Chrysler Crossfire, the Ferrari 360 Modena convertible, ...

Since the XLR is based on Corvette architecture, this should be relevant.

The relevant quote is: "Additional structural bracing is employed to keep cowl shake at bay and the car even passes federal rollover standards...." (something that convertibles are not required to pass...)

http://www.edmunds.com/news/autoshow/articles/101372/page015.html

Also, as Gordon87 pointed out, there are rollover hoops behind the seats for additional protection. (see pic)

Thanks, I didn't see those hoops in the 360 view on cadillac's site.

Also does the corvette test really apply since the corvette doesn't have the hoops but the XLR does?

I'm not positive that the XLR would pass the rollover like the Corvette, but I would bet it would.
They say the reason the reinforcements were added was to reduce cowl shake. This may be due to the LS2's 'lopey' idle, but I can't imagine them reducing refining techniques for the XLR.
Maybe somebody around here has the inside scoop.
Either way, it seems pretty safe. (or as safe as a rollover could be in a vert)
I wonder if there are ANY increases in safety with the top up? Probably not, but I guess it's possible.

Cadillac advertises the hardtop itself as a safety feature.

So you plan on rolling a XLR-V or what? It's hard to roll a sedan, not to mention a top-of-the-line Cadillac sports car. But if you did...

http://www.wreckedexotics.com/corvette/corvette_20040403_002.jpg

Your XLR-V will look close to this:helpless:

http://www.wreckedexotics.com/corvette/corvette_20040108_002.jpg

Hardtop seems to give you a little more headroom in the same situation...