We are a small NY distribution company and are thinking about offering the following maternity or medical leave policy:

8 Weeks of Job Perservation, 2 months medical coverage at existing plan rates if on compnay insurance, pay-out on any and all vacation, personal or sick time.

What are good standards to use and what legal concerns are there in offering the following. 

I don't think you have any legal concerns with having that policy.  I think you may have legal concerns when it is later enforced unequally.  If you can ensure that it is enforced fairly, it's a nice thing to do for your employees.  I would put a minimum service time in there.

Job preservation is going tough on small companies.  From a practical standpoint, I would remove that or define it narrowly in the policy (job preservation means there will definitely be some job available but not necessarily the one vacated).