Curt, I looked hard, and couldn't find anything. Then one day a nice person gave me a usable 5x7. I have had several close misses with 8x10. I'm tired of waiting too. A buddy has given me an 11x14 copy camera. I'm going to try and make that work. I know you have more tools and skills than I do, so maybe it's just the best option. When the great one falls in your lap, you can consider passing on the other to somebody you mentor.
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You are absolutely right, I think a copy camera can be a good alternative, it does seem that when a person stops looking one pops up. It's interesting how AA started out with a bank of light bulbs and opal glass then evolved to a cold light grid. Shows how adaptation might be the answer instead of looking for some huge machine. Also, never internet with a headache.
I hope you can get yours to work, it sounds good, enlarging up to 11x14 could be a plus if possible. I looked into making my Beseler 45 into a 5x7 and found that a 5" extension and the 5x7 cold light I already have will work. I would need to make a negative carrier but that's all. This is what I might do in the mean time. No cutting of the original enlarger, just an extension to raise the light source and negative up. I have an extra 45 head that I was going to cut up to make one but in testing I found that at 5" there is no light cut off and with my Schneider Componon 180 lens it works out fine.
Curt