Hi,
I'm confident that I can do this for you. I've been in the role of software architect and of system analyst a few times and have experience in gathering and structuring user requirements.
60-70 use cases for a system is a lot. Most often when you have this much, the use cases aren't well defined. I only saw a system with this number of use cases once, and that was a truly huge system. Therefore for my bid I estimated an amount of 20 use cases, and in total 60-70 scenarios within those use cases. Furthermore my bid includes the use case model, the supplementary (non-functional) specifications and activity diagrams describing the business process flows. Please send me the manual and other requirements documents you may have so I can make a final bid.
If you require my resume or more information please do not hesitate to contact me as well.
Regards,
Jeroen Voogt