What are the good sites out there?

Looking for a 1990's Hiram Walker Ten High Ten bottle.

master of malt has old bottles every now and then. keep an eye out there

https://www.masterofmalt.com/distilleries/hiram-walker-and-sons-whisky-distillery/

If you have a facebook account, join Bourbon Secondary. It is a closed group but they approve pretty fast.

Search for Alan Atkins. He just posted the below. Appears to be what you are looking for: (BIN is Buy It Now - read rules at sticky once approved)

BIN - 1990 Ten High
Ten High, 1990 (bottle stamp), 1 LITER
$55 Shipped - for 1 bottle
Each additional bottle add $45
Each has faux tax strip intact, and in similar good condition. Some variation exists.
ppff only, conus only
TERMS: Ships day after BIN & payment (except Sunday). All BINs must be paid same day. I assume delivery with "no signature required" is applicable unless you specifically state otherwise. Bottle has strip, so can't be tightened. Will secure to prevent any leakage, but it's possible to have a small amount with these old bottles.
8 bottles available in this listing.
X-posted.