Look for GL1000 headlight buckets - chrome steel. Frequently found on eBay for $20 or less. Part # is
HM-27M-S (not a Honda part # this model number is also found on brands other than Honda - must have been a supplier to multiple companies or sumpthin)
Honda part # for 1975 & 1976 GL1000 bucket is 61301-371-003. Its also listed at $95 on hondaparts-direct.com, new.
They are a really kewl replacement for that stock black plastic silliness and you can still use your present stock bulb and holder ring thingies.