Hi president1201,
This was a pretty tough search and unfortunately I was not able to locate any suppliers that seemed reliable. There are a number of suppliers based in China but I am quite hesitant to mention any on the forum.
Also, if you need the motherboard for personal use, I have read on the Blackberry Forums @ crankberry.com that it would be better if you just buy a new phone.
I did find these sites that might be able to help you -
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I suggest contacting them directly, hopefully they can help you out in sourcing the motherboard you need. But please note that we cannot vouch for these companies since we have not dealt with them in the past or currently.
All the best :)