One of the higher (depending on what these contingency plans were addressing...) network with other small consultants, and find a group you trust.
While your one item relates to 'replacement' this deals with the 'finding work' part.
It is critical in some circumstances to be 'bigger', some clients just do not like dealing with the 'little guy'.
Having a small group of consultants you work with, and TRUST, you can speak with them about larger efforts, and get real good information for bids, and support on the deals when you get them.
I use this strategy regularly, and have found it invaluable in getting some larger clients.
Additionally, using other 'large firms' as the primary on a contract and having a standing or quick 'corp to corp' agreement that you can use will help get more work, and create the stability to grow your consultancy.
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