Occasionally I have Hubs that have gone over 2,000 words and when possible, I have divided them into 2 or more hubs (usually when I divide each gets longer). The other choice is to make a table of contents. I did this once before and again on a Hub I just published. Hubber SidKemp wrote this Hub on how to do it: http://hubpages.com/community/TOC
Maybe this will also be a solution to your problem.
I don't know how a longer hub affects advertising area (I suspect there are no more or no less ads on a long Hub unless you add Amazon or eBay capsules making the Hub even longer). Long Hubs can keep your reader engaged for a longer period of time which, I believe, helps the Hubs status with Google. But, others may feel readers will get turned off by a long Hub. They want their info short and sweet.
I just write what I have to say and go with it.