Where do I purchase high-powered LED spotlights?

Are you referring to MR 16 LED lamps, normally installed in conventional track lighting fixtures? They come in flood, but haven't figured out how to produce a narrow spot, like for accent lighting. Directly from the source, there is www.dorcydirect.com.

I apologize! I should have said floodlights.

Are these to replace outdoor floodlights? Like PAR 75 (watt) or PAR 90 Halogens? Or, gawd forbid, R 75's and R 90's?

There are no inexpensive retrofits with LEDs, at least until China becomes a source and the imported LEDs any Japanese, Korean are American companies import are totally unreliable. They eat more energy than claimed, are way off color temperature to halogens and last about three days

The existing reliable retrofits are way below 20 watt draw. There is no 60 watt floods, but there are 50 watt.

Can't guarantee the quality of this product but for the equivalent lumens, $ 20.00 isn't bad -- I'd also try Amazon.com.

http://www.greenercountry.com/products/4W-LED-PAR-38-ACCENT-FLOOD-LIGHT--%28equiv.-45W-incand.%29.html

As I thought, the closest to what you're stating you need in any new reliable product is still about $ 100.00 -- buy inferior products with caution, especially from China (like above), as the quoted specs (including the life) will be a lie. You're likely going to pay maybe less than half when the Chinese products start flooding the market, except it's the same problem as with halogen lamps. You have to buy three or four to actually get the life of the $ 100.00 lamp, which is conservative at 50,000 hours -- on a surge protection system, it would probably be more like 200,000 hours.

http://www.ledenergysolutions.com/_apps/led_store/product_details.php/28/63

Amazon has what is the equivalent of 65w, and, of course, they are much close to true daylight than conventional halogen:

http://www.amazon.com/150-LED-Par-Floodlight-White/dp/B000IZCUXW/ref=sr_1_1?ie=UTF8&s=hi&qid=1253825456&sr=8-1