what about if in the lease instead of only saying I could come after them for the full term of the lease, what if I spelled it out that they could pay 2 months rent penalty in order to be released from the lease and released from me coming after them for the full term? Does something like that ever happen?
Happens a lot with more experienced landlords. It's a good idea.
I've handled my fair share of broken leases over the years. First off, the popular opinion is that the safety deposit is a sacred cow not to be messed with. I've found Louisiana case law stating differently, but you have to be very careful with the language in your lease. But I would be comfortable arguing that the deposit can be liquidated damages if provided for properly in the lease.
Second, collecting is tough. You generally have two options when a lease is broken: (1) eviction + $ for rent due + damages to property OR (2) accelerated rent. But they technically have the right to stay in the property when you sue for accelerated rent. If you re-let the property then you have mitigated and they will not be required to pay those amounts you received from a subsequent tenant.
I'll email you my cell/office and you are more than welcome to give me a buzz if you'd like. There are a lot of variables that determine your options.