I would just like to say that this thread is typical of every thread about different work permits....
There are lots of different work permits, and several variations of an 'L' or a 'B' permit.
To summarise what has been said above, and I'd be curious if these rules can be applied to every permit question on this forum:
1. There is a huge difference between EU and Non-EU permits, so don't talk to anyone who has an EU permit because they have completely different rules.
2. The most significant difference (in my opinion) between the NON-EU L and B permit is that with an L your spouse is not entitled to work, but with B they can. Otherwise, L's can be renewed to become B's. But it's unusual to go from a B back to an L.
3. The 'validity dates' of your permit should be on your card, but that gives no indication of whether or not the authorities will renew the permit for you again.
4. Your employer should have a copy of a document which tells them your exact status - short or long term, tied or not tied, and they probably have a reasonable idea of whether it will be renewed or not.
5. Most employers will have experienced applying for new permits or renewals and having them denied, so they will probably be reluctant to tell you anyway, and if they already know that it won't be renewed, they probably won't tell you because it will undermine the working relationship...
6. The immigration authorities do check work contracts as part of the approval process, and are unlikely to approve a contract if the salary is not within their reasonable limits, so they do appear to discourage organisations from bringing in foreigners who are cheaper than locals...
7. The permission to work in Switzerland is an arrangement between your employer and the government. You can't really go around and organise things for yourself, and it probably won't be appreciated by the authorities, unless your employer is doing something that is incorrect or inappropriate (harrassment, abuse of contract terms, not paying you according to your contract, lying to you about your status)...