You might want to try taking a lube that's as close to unflavored as possible and adding some of your own flavoring. I'd stay away from any sugar, but maybe some dietetic sweetener and an extract would work.

The problem with lubes and cough syrup both is that they're often trying to cover up a noticeable taste with another one. With cough syrup they're also trying to keep it from tasting "too good", and it's very likely that the lube manufacturers use the same flavorings because they're known to work well in pharmaceutical type products.

It seems that they should just stop using that flavor all together.

I got a sample pack of Lubricants, and the Durex brand isn't bad. It is all fake tasting as far as I'm concerned, but it was more candy like than medicine.