Can anyone provide/point to a proforma tenant centric 60 day lease termination clause to be added to a standard rental agreement once a verbal agreement is accepted?

I doubt it. This is a matter of negotiation. A landlord doesn't have to provide an early termination clause.

The terms should be simple:

Tenant reserves the right to terminate this lease prior to its expiration by giving 60 days notice and paying a penalty of 2 months rental.

Of course the number of days notice and the amount of the penalty are items for negotiation.

"Tenant shall have the right to terminate this lease upon 60 days prior written notice to Landlord."