Do you mean square like the attached image?
I get the here, prices are good in quantities, shipping is cheap. Expect a couple of weeks...
**broken link removed**
They have bars and stuff like that too. Everything I've gotten has been good, high brightness. The piranha LEDs are easy to fry, really need to be careful driving them as recommended in the data sheet. I've had some whites running off the first LM317 constant current circuit I built on a breadboard for almost a year, non stop. Not really bright enough to work by, but good enough to find stuff on the bench.