I can do this.
I would write it either in Python or Ruby. I have existing libraries and code at hand which can help. Multithreaded design is a given.
First we need to meet and discuss your requirements. After this meeting, I will create the software design and record a simple presentation (I do this with all my projects) on the workings of the code.
If you want to proceed further, please think about the answers to the following questions:
1) What are your data sources and sites you want to scrape
2) What do the tables on the database need to look like
3) What environment will the spider be running in
4) Do you need to tunnel through proxies
5) Do you need cloaking
6) Does the application run on one VM or is it distributed across multiple VMs
7) At what frequency do the sites need to be scraped / re-scraped
8) What type of user interface do you want
I love working on spiders and scrapers and have significant experience with them.
Contact me to discuss further.
Best,
Erdem
PS - The quoted price is for a command line spider that runs as a deamon on an interpreted language. If you want something with a user interface, it's going to cost more.