What really made them stand out is that the LEDs that were used in this 4" white round fixture. It was so blue!!! I guess colortemp was 5500K which is pretty much what all white LEDs are nowadays. (There is a few exceptions.... I have found warm white LEDS, but they are too new and still on the expensive side for truck applications, I guess).
I have not been able to locate any of those 5500K white truck lamps - they might be cool to use as DRLs or even home lighting if they are $10-20!
They might end up looking tacky with 5500K... Depends on what car I guess....

I see those 4 inch white truck led modules on ebay from time to time, i wouldn't imagine that they would be too white/white and more of a white/blue since, as you say, white leds are usually real high in the color temp scale.....

they're quite expensive though, a pair of those 4 inch white modules can go for 100 on ebay, on average. on the other hand, the red and amber 4 inch led modules go for around 30/pair on ebay. a pretty large price difference as you can see.

http://www.buytruckstuff.com/s_product_gp.asp?selcategory=34

The problem is that they are really back-up lamps (>80 to <500 cd on-axis)and not as intense as a real DRL (>500 to <3000 cd on axis)

Were these the Grotes that you saw?

By the way, Ott's friction supply on ebay (search for frictionsupply) has some of the best prices on Grote LED lamps, harnesses and other items that I have ever seen. Fast shipping and great customer service too. So far I have used primarly 100% Grote stuff for my LED tail project, including a Grote flasher. I purchased it all from John @ Ott's and I didn't spend much either.

flasher-$11.50 (may not be what I thought it should be)
4 Grote high count 4" round $14 each
2 Grote 2.5" markers, $7.50
pigtail harnesses are $1 each but I made my own since I forgot to order them

Sorry, this got a bit more offtopic than I had planned
Ian