Thanks for the help guys! I looked at the IPF bulbs and woah, were they expensive! They were out of my price range for this project spotlight because I'd rather put that money towards an HID upgrade.
I decided to buy the Hella H83140011 today, which was what I originally had been considering. It's in my price range and it's comonly available at various speed shops and 4x4 shops. I placed an order for one so hopefully I'll be able to start modifying my new Costco spotlight next week when/if it comes that early.
In case anyone is looking for this same halogen bulb, note that when I was shopping at both local and mail order places, most of them didn't have them in stock. They also didn't normally stock these bulbs and they only bought them from Hella when they got an order for them. I called one of my local hangouts, 4 Wheel Parts, a 4x4 shop, since it was listed on their website and they had to order it directly from Hella. The shipping estimate on that was ten days, which was too long for me. So instead I bought it from Newegg.com, which listed it as "in stock."
I'll post here if I notice an improvement after I drop in the new bulb.