That's been happening for a long time, but it is against eBay policies. To counter it, eBay added a policy allowing them to pull any auction that had "excessive" shipping charges. Unfortunately sometimes they use the policy to pull auctions that have shipping legitimately based on what the post office charges.
Anyway, I'd recommend against doing it unless you want to risk your auctions being pulled by eBay. The fees may be high, but they're planning to lower them somewhat now that the head of the company is leaving.