I have just started such a campaign using the rules in Bastion Press "Airships" and the rules in "Swashbuckling Adventures" I found the alternative character classes and equipment section to be very useful.
The only drawback is the lack of magic using classes presented in the book. That is easily remedied by bring in magic from other sources.
I recommend SA for this type of campaign. I found it to be a little pricey but worth it.
