Regarding Dwarves, I've always pictured them more grotesque because:
- They are harder than Men (can carry heavier weight being shorter). This strongly suggests wider bones and bigger muscles.
- They were called the Naugrim (Stunted People) and they were taken as minions od evil in the first encounters with Elves. If they were bearded version of the Elves (perfect human proportions) they probably wouldn't.
This image from the German film Die Nibelungen is quite close to my vision:

Sorry for the off-topic!
Going back to miniatures, best Tolkien Dwarves in my opinion are the old Fantasy Warrior line from Grenadier, even if the sculpts are a bit dated. Upper body and arms are Men size, legs are shorter and they're a bit hunchbacked and stocky.
