The most in-demand in-house roles are generalist positions with companies looking for a jack of all trades rather than a specialist from one particular sector. If you are able to do both corporate and commercial in equal measure you will be in demand. Those who have just covered one area will be less so.
The most popular locums are those who have got general commercial and corporate experience in both private practice and in-house roles. The reason for this is because in-house counsel tends to cover a very wide range of work across the board, but in a specific role are likely to just do certain tasks. However, there are a large number of corporate/commercial lawyers out there who have had very specific experience in one sector during their career, and quite possibly have no experience at all in another sector. In-house legal departments tend to want someone who can pick up a file and run with it, and not someone who may be in the legal 500 for their experience in aviation finance that wouldn’t have a clue dealing with an employment file.