It's always tricky trying to predict how long it will take to secure a visa. The "usual" route has always been to find a job first and have the employer handle the "hard part" but it looks as if the UK is switching over more and more to various points-based visa programs.

The HMSP visa program seems to be coming to an end, at least according to this from the UK Border Agency website (http://www.bia.homeoffice.gov.uk/workingintheuk/hsmp/):

"The HSMP will close completely on 29 June 2008. After this date all applications must be made under Tier 1 (General) of our new points-based system."

Is there any possibility that your employer might be able to help get your husband a visa with working privileges at the same time they are working on your three-year visa? I've heard of this being done as part of some expat packages - either the employer finds a job for the spouse in the company, or assists in finding a suitable position for the spouse nearby that would qualify them for a similar visa.

It's obviously in the interests of your employer to see that the two visas come through in roughly the same time frame.
Cheers,
Bev