Has anyone come across a P-61 Black Widow kit? This is one plane I have always been fascinated with and would love to build.

try precision cut kits.
They have three choices for your P61
My experience with them has been excellant. Their kits are laser cut and you will not be disappointed

Sweet, a 99" one. Noticed they also have a B17 kit, my friend will like that one, he has been wanting to fly one, and he still has years to go before his real one will be ready to fly.

You have a friend who owns a real honest-to-goodness Boeing B17? Or did I read that post wrong?

When I was active duty Air Force the reserve unit at my base (Dover) had a B-17 that they were restoring.  Its name is Shu Shu baby.  I wonder what happened to that.  That was back in 1982.

The B-17 from Dover was flown to the Museum of The USAF in Dayton Oh after the restoration was completed. Its currently on display as Shoo Shoo Shoo Baby as it was in the second world war